Bridge span replacement system

ABSTRACT

A vertically-adjustable gantry assembly installation adapted for removal or placement of a train bridge-span of the type which spans and is supported by two piers, comprises a gantry assembly positioned on load-bearing first ground-support locations, the gantry assembly comprising a gantry and a ground-engaging vertical support and lift system, the vertical support and lift system adapted for supporting a combined weight of the gantry and a bridge span in at least one operational vertical position above respective bridge span support-surfaces of the piers including a position corresponding to a disembarking plane in which the leg portions are extended from a stowed position to an extent at least sufficient for the gantry assembly to self-liftoff the pre-installation conveyance system onto the first ground-support locations to effect the gantry assembly installation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending application Ser. No.14/883,359; filed on Oct. 14, 2015, now U.S. Pat. No. 9,416,505, issuedon Aug. 16, 2016, which is a continuation of application Ser. No.14/169,445; filed Jan. 31, 2014, now U.S. Pat. No. 9,163,367, issuedOct. 20, 2015, which is a continuation of application Ser. No.13/787,461; filed on Mar. 6, 2013, now U.S. Pat. No. 8,671,490, issuedMar. 18, 2014. The disclosures of all of these applications areincorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to a method, system, apparatus andinstallation for replacing a train bridge span.

BACKGROUND OF THE INVENTION

Trains that travel through urban and rural areas need to cross overroads, hilly terrain and terrain interrupted by other natural vehiclebarriers including bodies of water. Train tracks crossing a train bridgeare often supported on a replaceable bridge span supported by two piers.Bridge spans can last for decades but increasingly undergo weakeningcorrosion, develop faults and eventually need to be replaced.

Bridge spans can weigh, on average, as much as 150 tons, and can be aslong as 30 meters so that they span two supporting piers. Accordingly,replacing a bridge span can pose considerable challenges.

For example, a train bridge may be located in areas that are difficultto access with cranes and other types of conventional heavy equipment ofthe type needed to replace a 150 ton bridge span. For example, it isknown to use specialized barges and ground equipment to assist inremoval and installation of a bridge span from a roadway or waterwaybeneath the bridge. However, access from beneath a bridge is onlypossible where the underlying area is accessible by large vehicles ornavigable by large floating vessels.

If multiple bridge spans need to be replaced on a particular bridge, aspecialized gantry crane may need to be constructed on site in a mannerwhich enables the crane to be sequentially re-positioned on more thanone pair of adjacent piers.

Furthermore, a site of span replacement may be an environmentallysensitive area that would be damaged by bringing in conventional orspecialized equipment.

Furthermore, replacing a bridge span may interrupt train traffic for aconsiderable period of time. The down-time costs railway companies andthe industries they service large sums in lost time and/or revenues.

Accordingly, there is a need for a rapid, agile, broadly usable andenvironmentally safe form of train bridge span replacement thataccommodates span removal and installation at single and multiplebridge-span replacement sites.

SUMMARY OF THE INVENTION

The invention will now be described in several aspects including agantry assembly, a system in which the gantry assembly is a component,in which different conveyance systems are used in cooperation with thegantry assembly, a gantry assembly installation in which the gantryassembly is installed at a particular location and in a particularmanner, a method for installing a gantry assembly at a bridge spanreplacement site, a method of removing an existing bridge span and amethod of installing a new bridge span.

According to one aspect, the invention is directed to avertically-adjustable gantry assembly installation as defined below:

A vertically-adjustable gantry assembly installation adapted for removalor placement of a train bridge-span of the type which spans and issupported by two piers, comprising:

A gantry assembly positioned on load-bearing first ground-supportlocations, the gantry assembly comprising a gantry and a ground-engagingvertical support and lift system, the gantry assembly adapted to supporta gantry conveyance system;

the vertical support and lift system adapted for supporting the gantryin at least one operational vertical position above respective bridgespan support-surfaces of the piers including a position corresponding toa disembarking plane in which the leg portions are extended from astowed position to an extent sufficient for the gantry assembly toself-liftoff the pre-installation conveyance system onto the firstground-support locations to effect the gantry assembly installation.

Optionally, the vertical support and lift system is operativelyassociated with a power system and a control system, for example anintegrated or separate hydraulic power unit which is controlled by acontrol system to extend the legs from a stowed position in order toeffect a gantry installation.

According to another embodiment the invention is directed to avertically-adjustable gantry assembly installation adapted for removalor placement of a train bridge-span of the type which spans and issupported by two piers, comprising:

A gantry assembly positioned on load-bearing first ground-supportlocations, the gantry assembly comprising a gantry and a ground-engagingvertical support and lift system, the gantry assembly adapted tooperatively associated with a gantry conveyance system adapted tosupport the weight of the bridge span and a ground conveyance system;

the vertical support and lift system including leg portions havingground engaging portions and a gantry connection portion including anoutrigger portion, the vertical support and lift system adapted forsupporting a combined weight of the gantry and a bridge span in at leastone operational vertical position above respective bridge spansupport-surfaces of the piers including a position corresponding to ahorizontal transport plane in which the bridge span is conveyed by thegantry conveyance system along at least a portion of gantry.

The gantry assembly installation is adapted to transfer a loadcorresponding to the weight of the bridge span from the gantryconveyance system to the ground conveyance system.

The gantry assembly installation is adapted to transfer a loadcorresponding to the weight of the bridge span from the groundconveyance system to the gantry conveyance system.

The load corresponding to the weight of the bridge is optionallytransferred in stages, for example, a load corresponding to a forwardend of the bridge span may be transferred first followed by a loadcorresponding to a rearward end of the bridge span.

In a related aspect, another embodiment:

A vertically-adjustable gantry assembly installation adapted for removalor placement of a train bridge-span of the type which spans and issupported by two piers, comprising:

A gantry assembly positioned on load-bearing first ground-supportlocations, the gantry assembly comprising a gantry and a ground-engagingvertical support and lift system, the gantry assembly adapted tooperatively associated with a gantry conveyance system and a groundconveyance system;

the vertical support and lift system adapted for supporting a combinedweight of the gantry and a bridge span in at least one operationalvertical position above respective bridge span support-surfaces of thepiers including a position corresponding to a disembarking plane inwhich the gantry assembly is adapted to self-liftoff thepre-installation conveyance system onto the first ground-supportlocations to effect the gantry assembly installation, the verticalsupport and lift system including leg portions, the leg portionsincluding ground engaging portions, the ground engaging portionsincluding overhang portions of a ground support structure, the legportions adapted to be used with or operatively associated with analignment system, the alignment system optionally including an abutmentmember (e.g. on the ground engaging portions or overhang portions of theground support structure) for aligning the overhang portions withground-supported portions of the ground support structure.

In a related aspect, the invention is also directed to avertically-adjustable gantry assembly installation adapted for removalor placement of a train bridge-span of the type which spans and issupported by two piers, comprising:

A gantry assembly securely positioned on load-bearing firstground-support locations, the gantry assembly comprising a gantry and aground-engaging vertical support and lift system, the vertical supportand lift system operatively associated with a power system and a controlsystem, the gantry assembly adapted to be operatively associated with agantry conveyance system, the gantry assembly adapted to be transportedin a horizontal position to a site for placement or removal of a bridgespan by a pre-installation conveyance system (27) including at least onerail car;

the vertical support and lift system adapted for supporting a combinedweight of the gantry and a bridge span in operational vertical positionsabove respective bridge span support-surfaces of the piers including aposition corresponding to at least one horizontal transport plane inwhich the bridge span is conveyable relative to the gantry by the gantryconveyance system and a disembarking plane in which the leg portions areextended by the power system from a stowed position to an extent atleast sufficient for the gantry assembly to self-liftoff thepre-installation conveyance system onto the first ground-supportlocations to effect the gantry assembly installation.

Additional embodiments of the various embodiments of a gantry assemblyinstallation, according to one aspect of the invention, as definedabove, will now be summarized.

Optionally, the vertical support and lift system includes:

a load bearing first vertical support assembly operatively connected tothe gantry proximalto a first end thereof; and

a load-bearing second vertical support assembly operatively connected tothe gantry proximal to a second end thereof.

Optionally, each vertical support assembly including at least one legportion having a ground engaging portion and a gantry connection portionfor connecting the leg portions to the gantry, the vertical support andlift system including or adapted to be operatively associated with apower system and a control system to vary the linear vertical distancebetween the ground engaging portion of a leg portion and the gantry tocontrol the vertical height of the gantry.

Optionally, the lift system is hydraulically powered. Optionally, thepower system includes a hydraulic power unit supported by the gantryassembly.

Optionally, the gantry conveyance system is operatively connected to abridge span support system, optionally in the form of a bridge spanconnection system for suspending the bridge span from the gantryconveyance system, the gantry conveyance system and a bridge spanconnection system configured to provide at least two conveyable,separately locatable, suspension means for suspending the bridge spanbeneath the gantry.

The suspension means are optionally two separately locatable vehiclesconfigured to travel along a track system supported by the gantryassembly. Optionally, the vehicle(s) is/are adapted to be hydraulicallypowered. Optionally, the power system powers the vertical support andlift system and the vehicle(s).

Alternatively, the suspension means may vehicles operatively associatedwith winches.

Optionally, the vehicle(s) is/are adapted to independently support theweight of a bridge span and configured for conveying a bridge span in asubstantially horizontal plane along at least a portion of the length ofthe gantry, movement of bridge span relative to the gantry via thegantry conveyance system defining at least a first portion of thehorizontal transport plane, the gantry conveyance system adapted to beoperatively associated with a bridge span connection system configuredfor suspending the bridge span from the gantry conveyance system,beneath the gantry, for conveyance in the horizontal transport plane.

Optionally, the gantry assembly installation is operatively associatedwith a load-bearing ground conveyance system positioned at load bearingsecond ground-support locations, the ground conveyance system includinga support portion for supporting a load comprising the weight of abridge span, the ground conveyance system adapted to be transportedalong a path beginning at the end of the bridge span and extending awayfrom the bridge span.

Optionally, the gantry assembly and/or the gantry conveyance systemdefining vehicle position limits that delimit a maximum horizontaltravel distance that the at least one vehicle can travel in thehorizontal transport plane when supporting a load comprising at least aportion of the weight of the bridge span, a vehicle position limitand/or the path accommodating conveyance of the bridge through at leasta threshold horizontal conveyance distance required for transferringload support from the gantry conveyance system to the ground conveyancesystem and/or from the ground conveyance system to the gantry conveyancesystem.

Optionally, the gantry assembly and/or the gantry conveyance system atleast partially define bridge span position limits that delimit aminimum horizontal transport distance over which the bridge span can beconveyed with at least partial load support from the gantry conveyancesystem, the minimum horizontal transport distance extending beyond thefirst ground locations.

Optionally, the gantry connection portion includes an outrigger portionconfigured to laterally distance the at least one leg portion of atleast one vertical support assembly from lateral perimeters of thegantry, whereby the outrigger portion is adapted to accommodate passageof a bridge span, having a footprint wider than the gantry, between theleg portions of at least one vertical support assembly to accommodatetransfer of load support from the gantry conveyance system to the groundconveyance system and/or from the ground conveyance system to the gantryconveyance system.

Optionally, the at least one rail car of the pre-installation conveyancesystem define a conveyance system footprint area including lateralperimeters, the gantry optionally configured to have a gantry footprintarea having lateral perimeters which fit within the lateral perimetersof the pre-installation conveyance system, the outrigger portion adaptedto position leg portions of at least one vertical support assemblybeyond the lateral perimeters of the footprint area of thepre-installation conveyance system, to clear the lateral perimeters ofthe pre-installation conveyance system, when the gantry legs are loweredto effect a gantry installation.

Optionally, the leg portions are connected to the outrigger portions ofthe gantry connection portion (e.g. extend therefrom) and the outriggerportion together with the leg portions of at least vertical supportassembly are rotationally mounted with respect to positionally-fixedportions of the gantry connection portion, for movement about a verticalaxis perpendicular to the longitudinal axis of the gantry between astowed position in which the outrigger portion and leg portion arerotated towards the gantry and a laterally extended installationposition, the outrigger portion and leg portions fastened to thepositionally-fixed portion to prevent rotation and accommodate full loadsupport in the installation position.

Optionally, the outrigger portion of the gantry connection portion ishingedly-mounted to a positionally-fixed portion of the gantryconnection portion.

The gantry assembly defines a footprint on the pre-installationconveyance system. Optionally, the lateral perimeters of the gantryassembly footprint lie within the lateral perimeters of the footprintarea of the pre-installation conveyance system when the gantry assemblyin supported on the pre-installation conveyance system in a stowedposition.

Optionally, the lateral perimeters of the gantry assembly footprint,when in the stowed position, falls within existing railway clearancesfor the delivering the gantry assembly to or from a site of placement orremoval of a bridge span.

Optionally, the overall footprint of the gantry assembly supported onthe pre-installation conveyance system is accommodated by existingrailway clearances by pre-defined lateral tolerances.

Optionally, the overall pre-installation conveyance envelope of thegantry assembly supported on the pre-installation conveyance system isaccommodated by existing railway clearances by pre-defined lateral andvertical tolerances. Optionally, the post-installation conveyanceenvelope is similarly accommodated.

Optionally, each vertical support assembly comprises an outriggerportion and two leg portions, the leg portions adapted to be contractedby the vertical support and lift system to occupy a compactconfiguration which provides suitable ground clearance in the stowedposition.

Optionally, the first ground-support locations are ground locationsadapted for load support.

Optionally, the first ground locations include a pre-installed groundsupport structure.

Optionally, the ground support structure includes ground-supportedportions and overhang portions which have no direct ground support.

Optionally, the ground support structure is a ground engaging loadbearing support beam installed over load supporting ground material atground locations corresponding to planned ground positions of groundengaging portion(s) of the first vertical support assembly and/or thesecond vertical support assembly. Optionally, the support beams aresteel tie beams at least partially supported on ground material underportions of a train track leading respectively to and from an existingbridge span.

Optionally, these support beams are positioned to have a top-surfaceheight which provides load-bearing support to the under-surface oftrain-track rails proximal to the first ground locations when the tiebeams are supported at respective ground locations formerly occupied byrailway ties.

Optionally, the ground engaging portions of the leg portion(s) of thefirst vertical support assembly and the second vertical support assemblyare adapted to be securely fastened to the support beam.

Optionally, the support beam has connection portions for connecting tothe ground engaging portions (e.g. foot portions) of the leg portionsand the foot portions have mating connection portions.

Optionally, the tie beam may consist of a pre-installed middle sectionand two end sections which are secured to the middle section when thegantry assembly is installed at the first ground support locations.

Optionally, the ground conveyance system comprises at least one rail carsupported on load-bearing second ground locations in the vicinity of thebridge-span support surface of a pier, the ground conveyance systemadapted to travel on a path defined by rails of a track used totransport the gantry assembly or a bridge span to or from a gantryassembly installation site.

The path preferably extends a vehicle position limit on at least oneside of the gantry by a distance at least sufficient to transfer loadsupport from the gantry conveyance system to the ground conveyancesystem, optionally by a distance sufficient to convey the bridge span toan alternate train track.

Optionally, the horizontal transport plane is vertically circumscribedby an upper vertical clearance limit defined by a lower edge of thegantry and a lower vertical clearance limit defined by a bridge spansupport surface of the ground conveyance system.

Optionally, the bridge span connection system includes a plurality ofstraps sized to suspend the bridge span beneath upper vertical clearancelimit.

Optionally, the control system is operable to raise the gantry into avertical position in which the lower vertical clearance limit is aboveand clears the support portion of the first ground conveyance system,the control system operable to lower the bridge span onto the supportsurface of the ground conveyance system.

Optionally, the pre-installation conveyance system comprises a supportportion adapted to support the gantry assembly. Optionally, the gantryassembly has a surface configuration adapted to be supported in asubstantially horizontal position on the support portion. Optionally,the gantry has a flat bottom and the pre-installation conveyance systemhas complimentary support surfaces e.g. flat support bed, optionallyoutfitted with support portions that enable the gantry to swing asnecessary when the train track curves e.g. a bolster.

Optionally, the vertical support and lift system is adapted to be usedwith or directly operatively associated with (e.g. secured to) to anoverhang ground-support system for example overhang portions of a groundsupport structure. The term “ground support structure” is used to anystructure used to introduce a load-bearing support feature and/or astability feature e.g. in order to enhance or form the first, second orthird ground locations. The ground support structure is optionallyoperatively associated with an alignment system, for example a verticaland/or lateral alignment system, optionally including an alignment meansfor aligning the ground engaging portion of the gantry legs withoverhang portions of the overhang ground support system, for example foraligning connection portions that enable the ground engaging portions tobe connected to the overhang portions or the overhang portions to beconnected to ground support portions of the overhang ground supportsystem. The alignment means may be a vertical alignment means, forexample a projecting abutment portion or other stop means to gauge ordefine stop positions when lowering the leg portions from off thepre-installation conveyance system, for example, so that the overhangportions of the overhang ground support system are urged to be arrestedinto alignment with the ground support portions of the overhang groundsupport system. Thus, the overhang ground support system defines orprovides first ground support locations for supporting the groundengaging vertical support and lift system. Optionally, the groundengaging portions of the leg portions are pre-attached to and includethe overhang portions of the ground support structure. In amethodological aspect the method of the invention optionally includes,preliminary to effecting a gantry installation, a preliminaryground-support preparation step optionally including the step ofinstalling the ground support portions of an overhang ground supportsystem e.g. in the form a ground support structure like a beam.Optionally, the alignment system includes accurate positioning the railcarts on the train track (x axis), accurate positioning of the gantryassembly on the rail carts (y axis) along with lateral play in matingportions of the gantry leg and the ground engaging (e.g. shoe or foot)portion (the foot portion is pinned to the leg portion in a manner inwhich provides play in the Y axis) and controlled finally lowering ofthe gantry legs (z axis) aided by a vertical alignment system in theform of an vertical alignment means e.g. a laterally projecting abutmentportion.

Additional features of the gantry assembly installation are describedbelow with reference to other aspects of the invention.

For example, the gantry conveyance system may be associated with aspreader structure adapted for supporting the bridge span from bothsides of the gantry.

Optionally, the gantry conveyance system includes a track system whichincludes a track positioned on top or beneath the gantry.

Optionally, the gantry assembly comprises right and left portions spacedto provide clearance for suspension members belonging to a suspensionsystem, for example a bridge span connection system in the form ofstraps operatively connected to the undersurface of a vehicle ortrolley. The term “member” broadly refers to a part or portion, forexample of a structure or system. The suspension members are optionallybe cables which are adapted for use at a fixed operational length oralternatively are operatively associated with a winch or a strand jack.

Similarly, embodiments of the gantry assembly installation describedabove may apply to other aspects of the invention, even though they arenot repeated below.

According to another aspect the invention is directed to a gantryassembly for removal or placement of a train bridge-span of the typewhich spans and is supported by two piers, comprising:

A gantry;

A ground-engaging vertical support and lift system;

the gantry assembly configured to be transported in a horizontalposition to a site for placement or removal of a bridge span by apre-installation conveyance system (27) including at least one rail car;

the vertical support and lift system including:

a load bearing first vertical support assembly operatively connected tothe gantry proximalto a first end thereof; and

a load-bearing second vertical support assembly operatively connected tothe gantry proximal to a second end thereof,

the gantry assembly adapted to support a gantry assembly conveyancesystem, the gantry conveyance system adapted to support the weight of abridge span and configured for conveying a bridge span in a horizontaltransport plane along at least a portion of the length of the gantry,the gantry conveyance system adapted to be operatively associated with abridge span support system (e.g. a suspension system) for supporting thebridge span from at least two positions on the bridge span proximal tothe ends of the bridge span;

each vertical support assembly including at least one leg portion havinga ground engaging portion and a gantry connection portion for connectingthe leg portions to the gantry, the gantry connection portion includingan outrigger portion, the vertical support and lift system including oradapted to be operatively associated with a power system and a controlsystem to vary the linear vertical distance between the ground engagingportion of a leg portion and the gantry to control the vertical heightof the gantry, the vertical support and lift system adapted forsupporting a combined weight of the gantry and a bridge span in anoperational vertical positions above the respective bridge spansupport-surfaces of the piers including at least one positioncorresponding to the horizontal transport plane.

Optionally, the bridge span support system is a bridge span connectionsystem, the bridge span connection system optionally comprising straps.

Optionally, the gantry conveyance system includes a track systemoperatively connected to the gantry assembly;

the gantry assembly and/or the gantry conveyance system defininghorizontal bridge span conveyance limits that delimit a maximumhorizontal travel distance over which the bridge span can be conveyed bythe gantry conveyance system alone in the horizontal transport plane;

the gantry conveyance system configured to cooperate with a load-bearingground conveyance system including a support portion for supporting aload comprising the weight of a bridge span, the ground conveyancesystem adapted to be transported on a path extending away from an end ofa bridge span, a vehicle position limit and/or the path accommodatingconveyance of the bridge span through at least a threshold horizontalconveyance distance required for transferring load support from thegantry conveyance system to the ground conveyance system and/or from theground conveyance system to the gantry conveyance system.

Optionally, the gantry assembly and/or the gantry conveyance system atleast partially define bridge span position limits that delimit aminimum horizontal transport distance over which the bridge span can beconveyed with at least partial load support from the gantry conveyancesystem, the minimum horizontal transport distance extending beyond thefirst ground locations.

Optionally, as described above, the gantry conveyance system and bridgespan connection system are configured to provide at least twoconveyable, separately locatable, suspension means for suspending thebridge span beneath the gantry.

Optionally, as described above, the at least one rail car of thepre-installation conveyance system defines a conveyance system footprintarea including lateral perimeters, the outrigger portion adapted toposition leg portions of at least one vertical support assembly beyondthe lateral perimeters of the footprint area of the pre-installationconveyance system, to clear the lateral perimeters of thepre-installation conveyance system, when the gantry legs are lowered toeffect a gantry installation.

Optionally, as described above, the outrigger portion and leg portionsof at least one vertical support assembly are rotationally mounted, forexample, with respect to positionally-fixed portions of the gantryconnection portion, for movement about a vertical axis perpendicular tothe longitudinal axis of the gantry between a stowed position and alaterally extended installation position. Optionally, each verticalsupport assembly comprises an outrigger portion and two leg portions,the leg portions adapted to be contracted by the vertical support andlift system to occupy a compact configuration which provides suitableground clearance in the stowed position.

Optionally, as described above, the first ground-support locations areground locations adapted for load support, for example, by installing aground engaging load bearing support beam (9) installed over loadsupporting ground material at ground locations corresponding to plannedground positions of ground engaging portion(s) of the first verticalsupport assembly and/or the second vertical support assembly.

Optionally, as described above, at least one vertical support positioncorrespond to a disembarking plane in which the leg portions areextendable e.g. by a power system, from a stowed position on thepre-installation conveyance system to an extent at least sufficient forthe gantry assembly to self-liftoff the pre-installation conveyancesystem onto the first ground-support locations to effect a gantryinstallation.

Optionally, as described above, the outrigger portion is configured tolaterally distance at least one leg portion (preferably both) of atleast one vertical support assembly from lateral perimeters of thegantry, whereby the outrigger portion is adapted to accommodate passageof a bridge span, having a footprint wider than the gantry, between theleg portions of at least one vertical support assembly to accommodatetransfer of load support from the gantry conveyance system to the groundconveyance system and/or from the ground conveyance system to the gantryconveyance system.

Optionally, as described above, the gantry is configured to have agantry footprint area having lateral perimeters which fit within thelateral perimeters of the pre-installation conveyance system, theoutrigger portion adapted to position leg portions of at least onevertical support assembly beyond the lateral perimeters of the footprintarea of the pre-installation conveyance system, to clear the lateralperimeters of the pre-installation conveyance system, when the gantrylegs are lowered to effect a gantry installation.

Optionally, as described above, the first ground locations are groundlocations adapted for load support, for example, by installing a groundengaging load bearing support beam positioned over load supportingground material at ground locations corresponding to planned groundpositions of ground engaging portion(s) of the first vertical supportassembly and/or the second vertical support assembly, the groundengaging portions of the leg portions adapted to be secured to the loadbearing support beam.

Optionally, as described above, the gantry conveyance system comprisestwo separately locatable vehicles powered by a hydraulic vehicle powersystem, the vehicles operatively connected to a vehicle control systemfor controlling a respective position of the vehicle on the track systemincluding forward and rearward movement. Optionally, the control systemfor controlling the vertical support and lift system is a remote-controlsystem. Optionally, the vehicle control system is a remote-controlsystem. Optionally, the two remote-control systems are integrated into asingle control unit adapted to be controlled by a single operator.

Optionally, the vehicles are operatively connected to a spreaderstructure, the spreader structure oriented transversely with respect tothe longitudinal axis of the gantry for distancing two points ofsuspension of the bridge span from the center of gravity of a vehicle.Optionally, the spreader structure is configured to suspend the bridgespan from two sides of the gantry.

Optionally, the bridge span connection system comprises straps (e.g.webbing made of synthetic fibers, or steel cable, with a breakingstrength adapted to support a portion of the weight of the bridge span),each end of the spreader structure optionally displaced sufficientlyfrom a center of gravity of the vehicle to define a line of sightbetween a respective end of the spreader structure and a point ofcontact or connection of the straps to the bridge span, each end of thespreader structure operatively associated with a connector forconnecting a strap, for example a shackle, the webbing or cableoptionally looped around the shackle.

Optionally, the distance between connectors at opposite ends of aspreader structure is longer than the width of the gantry.

Optionally, the bridge span is outfitted with a connector that receivesa strap. Optionally, the connector is adapted to be attached to a lug onthe bridge span. Optionally, the connector is a shackle.

A connector is optionally configured so that straps move transverselywith respect to the longitudinal axis of the gantry to increasetransverse play of the straps with respect to the ends of the spreaderstructure or the bridge span.

Optionally, a connector is configured to permit the sling arm to haveplay in plane parallel to longitudinal axis of the gantry, for example,the connector attached to the spreader structure.

Optionally, as described above, the vertical support and lift system isa hydraulically powered, each vertical support assembly optionallycomprising two telescoping leg portions wherein the linear distancebetween the ground engaging portion of each leg portion and the gantryis adapted to be hydraulically varied by the power system.

According to another aspect the invention is directed to a system forremoval or placement of a train bridge-span of the type which spans andis supported by two piers, comprising:

A gantry assembly comprising a gantry and a vertical support and liftsystem including leg portions having ground engaging portions adapted tobe supported on first ground support locations;

the gantry assembly adapted to be transported in a horizontal positionto a site for placement or removal of a bridge span by apre-installation conveyance system (27) including at least one rail car;

the gantry assembly adapted to support a gantry conveyance system, thegantry conveyance system adapted to cooperate with a load-bearing groundconveyance system, the gantry conveyance system including or operativelyassociated with bridge support portions adapted to provide at least twopoints of support for supporting the bridge span from two positions onthe bridge span proximal to the ends of the bridge span;

the vertical support and lift system adapted for supporting a combinedweight of the gantry and a bridge span from first ground-supportlocations in at least one operational vertical position above therespective bridge span support-surfaces of the piers at least oneoperational vertical position corresponding to position(s) including atleast one horizontal transport plane and a disembarking plane in whichthe leg portions are extendable from a stowed position on thepre-installation conveyance system to an extent sufficient for thegantry assembly to self-liftoff the pre-installation conveyance systemonto the first ground support locations to effect a gantry installation.

Optionally, wherein the gantry assembly and/or the gantry conveyancesystem define bridge span position limits that delimit a maximumhorizontal travel distance that the bridge span can be conveyed in thehorizontal transport plane when supported by the gantry conveyancesystem; and

the ground conveyance system is adapted to be transported on a pathextending away from a ground position adjacent to an edge of an existingbridge span, a bridge span position limit and/or the path accommodatingconveyance of the bridge through at least a threshold horizontalconveyance distance required for transferring load support from thegantry conveyance system to the ground conveyance system and/or from theground conveyance system to the gantry conveyance system.

Other embodiments of the system for organizing removal and replacementof a train bridge span will now be described.

The system optionally comprising:

A gantry assembly comprising a gantry and a vertical support and liftsystem including leg portions having ground engaging portions adapted tobe supported on first ground support locations;

the gantry assembly adapted to be transported in a horizontal positionto a site for placement or removal of a bridge span by apre-installation conveyance system including at least one rail car;

the gantry assembly adapted to support a gantry conveyance system, thegantry conveyance system adapted for horizontally conveying a bridgespan in a horizontal transport plane relative to the gantry assemblyover distance sufficient to transfer a load corresponding to the weightof the bridge span in stages onto a support portion of a groundconveyance system, the gantry conveyance system including or operativelyassociated with a support portion adapted to provide support forsupporting the bridge span from two positions on the bridge span, thepositions proximal to the respective ends of the bridge span;

the vertical support and lift system adapted for supporting the gantryfrom first ground-support locations in at least one operational verticalposition above the respective bridge span support-surfaces of the piersat least one operational vertical position corresponding to position(s)including a disembarking plane in which the leg portions are extendablefrom a stowed position on the pre-installation conveyance system to anextent sufficient for the gantry assembly to self-liftoff thepre-installation conveyance system onto the first ground supportlocations.

Optionally, the vertical support and lift system is adapted forsupporting the gantry in the horizontal transport plane.

Optionally, the gantry assembly and the support portion are operativelyassociated with a lift system, the lift system adapted for raising abridge from the piers into the horizontal transport plane and lowering abridge span onto the piers from a horizontal transport plane.

Optionally, the gantry conveyance system is adapted for horizontallyconveying a bridge span in a horizontal transport plane relative to thegantry assembly over distance sufficient to transfer a loadcorresponding to the weight of the bridge span in stages from a supportportion of a ground conveyance system to the gantry conveyance system.

According a related aspect, the invention is directed to a system forremoval or placement of a train bridge-span of the type which spans andis supported by two piers, comprising:

A gantry assembly comprising a gantry and a vertical support and liftsystem including leg portions having ground engaging portions adapted tobe supported on first ground support locations;

the gantry assembly adapted to be transported in a horizontal positionto a site for placement or removal of a bridge span by apre-installation conveyance system including at least one rail car;

the gantry assembly adapted to support a gantry conveyance system, thegantry conveyance system adapted for supporting the weight of a bridgespan and configured for conveying a bridge span in a horizontaltransport plane along at least a portion of the length of the gantry,the gantry conveyance system adapted to cooperate with a load-bearingground conveyance system.

Embodiments of the systems as defined above will now be summarized.

Optionally, the gantry conveyance system is adapted to cooperate with abridge span connection system, the gantry conveyance system and bridgespan connection system cooperating to provide at least two separatelylocatable or independently locatable suspension means for supporting thebridge span from two positions on the bridge span proximal to the endsof the bridge span.

The vertical support and lift system is adapted for supporting acombined weight of the gantry and a bridge span in operational verticalpositions above the respective bridge span support-surfaces of the piersincluding, the operational vertical positions corresponding to the atleast one horizontal transport plane and a disembarking plane in whichthe leg portions are extended (e.g. by controlling a power systemoperatively associated with the vertical support and lift system) from astowed position on the pre-installation conveyance system to an extentsufficient for the gantry assembly to self-liftoff the pre-installationconveyance system onto the first ground support locations to effect agantry installation.

Optionally, the gantry assembly and/or the gantry conveyance systemdefine suspension means position limits that delimit a maximumhorizontal travel distance that the suspension means can travel in thehorizontal transport plane when supporting a load comprising at least aportion of the weight of the bridge span.

Optionally, the ground conveyance system is adapted to be transported ona path extending away from a ground position adjacent to an edge of anexisting bridge span, a suspension means position limit and/or the pathaccommodating conveyance of the bridge through at least a thresholdhorizontal conveyance distance required for transferring load supportfrom the gantry conveyance system to the ground conveyance system and/orfrom the ground conveyance system to the gantry conveyance system.

Optionally, as described above, the vertical support and lift systemincludes:

a load bearing first vertical support assembly (2) operatively connectedto the gantry proximalto a first end thereof; and

a load-bearing second vertical support assembly operatively connected tothe gantry proximal to a second end thereof

each vertical support assembly including two leg portions having aground engaging portions and a gantry connection portion for connectingthe leg portions to the gantry, the vertical support and lift systemincluding or adapted to be operatively associated with a power systemand a control system to vary the linear vertical distance between theground engaging portion of a leg portion and the gantry to control thevertical height of the gantry.

Optionally, as described above, the gantry assembly and/or the gantryconveyance system at least partially define bridge span position limitsthat delimit a minimum horizontal transport distance over which thebridge span can be conveyed with at least partial load support from thegantry conveyance system, the minimum horizontal transport distanceextending beyond the first ground locations.

Optionally, as described above, the gantry connection portion includesan outrigger portion configured to laterally distance at least one legportion (preferably both) of at least one vertical support assembly fromlateral perimeters of the gantry, whereby the outrigger portion isadapted to accommodate passage of a bridge span, wider than the gantry,between the leg portions of at least one vertical support assembly toaccommodate transfer of load support from the gantry conveyance systemto the ground conveyance system and/or from the ground conveyance systemto the gantry conveyance system.

Optionally, as described above, the at least one rail car of thepre-installation conveyance system defines a conveyance system footprintarea including lateral perimeters, the gantry configured to have agantry footprint area having lateral perimeters which fit within thelateral perimeters of the pre-installation conveyance system, theoutrigger portion adapted to position leg portions of at least onevertical support assembly beyond the lateral perimeters of the footprintarea of the pre-installation conveyance system, to clear the lateralperimeters of the pre-installation conveyance system, when the gantrylegs are lowered to effect a gantry installation.

Optionally, as described above, the outrigger portion and leg portionsof at least vertical support assembly are rotationally mounted withrespect to positionally-fixed portions of the gantry connection portion,for movement about a vertical axis perpendicular to the longitudinalaxis of the gantry between a stowed position in which the outriggerportion and leg portion are rotated towards the gantry and a laterallyextended installation position.

Optionally, the lateral perimeters of the gantry assembly footprint whenthe gantry assembly in supported on the pre-installation conveyancesystem in the stowed position lie within existing railway clearances forthe delivering the gantry assembly to or from a site of placement orremoval of a bridge span.

According to yet another aspect, the invention is directed to a methodof organizing installation or replacement of a train bridge span of thetype which spans and is supported by two piers (25) of a train bridge,each pier having and a bridge span support-surface (22), the methodcomprising:

using a pre-installation conveyance system including at least one railcar to convey a gantry assembly, supported in a horizontal position,into horizontal alignment with a plurality of load-bearing firstground-support locations, wherein the gantry assembly overlies anexisting bridge span supporting a train track, the pre-installationconveyance system defining a pre-installation conveyance systemfootprint area having lateral perimeters;

the gantry assembly comprising a gantry and a ground-engaging verticalsupport and lift system including leg portions each having a groundengaging portion for supporting the leg portions on respective firstground-support locations;

the gantry assembly adapted to be operatively associated with a gantryconveyance system and a bridge span connection system adapted forhorizontally conveying a raised existing bridge span in a horizontaltransport plane relative to the gantry assembly over distance sufficientto transfer a load corresponding to the weight of the existing bridgespan in at least one stage onto a support portion of a ground conveyancesystem;

the vertical support and lift system adapted supporting a combinedweight of the gantry and a bridge span in at least one operationalvertical position above the respective bridge span support-surfaces ofthe piers, and extending the leg portions into installed positions fromstowed positions on the pre-installation conveyance system, the at leastone operational vertical position including a position corresponding to:

the horizontal transport plane;

a pre-installation conveyance system disembarking plane, in which thegantry legs are extendable to self-lift the gantry assembly off thepre-installation conveyance system to effect a gantry installation; and

controlling the vertical support and lift system to lift the gantryassembly off the pre-installation conveyance system to position thefirst and second vertical assemblies on the first ground locations.

According to another embodiment of the method, the invention is directedto a method of organizing installation or replacement of a train bridgespan of the type which spans and is supported by two piers of a trainbridge, the method comprising:

using a pre-installation conveyance system including at least one railcar to convey a gantry assembly, supported in a horizontal position,into horizontal alignment with a plurality of load-bearing firstground-support locations;

the gantry assembly comprising a gantry and a ground-engaging verticalsupport and lift system including leg portions each having a groundengaging portion for supporting the leg portions on respective firstground-support locations;

the gantry assembly adapted to be operatively associated with a gantryconveyance system adapted for horizontally conveying a bridge span in ahorizontal transport plane relative to the gantry assembly over distancesufficient to transfer a load corresponding to the weight of theexisting bridge span in at least one stage onto a support portion of aground conveyance system;

the vertical support and lift system adapted supporting a combinedweight of the gantry and a bridge span in at least one operationalvertical position above the respective bridge span support-surfaces ofthe piers, the at least one position corresponding to:

the horizontal transport plane;

a pre-installation conveyance system disembarking plane, in which thegantry legs are extendable to self-lift the gantry assembly off thepre-installation conveyance system to effect a gantry installation;

Controlling the vertical support and lift system to lift the gantryassembly off the pre-installation conveyance system to position thefirst and second vertical assemblies on the first ground locations.

According to another embodiment of the method, the invention is directedto a method of organizing installation or replacement of a train bridgespan of the type which spans and is supported by two piers of a trainbridge, each pier having and a bridge span support-surface, the methodcomprising:

using a pre-installation conveyance system (27) including at least onerail car to convey a gantry assembly, supported in a horizontalposition, into horizontal alignment with a plurality of load-bearingfirst ground-support locations;

the gantry assembly comprising a gantry and a ground-engaging verticalsupport and lift system, the vertical support and lift systemoperatively associated with a control system and including leg portions,each leg portion having a ground engaging portion for supporting the legportions on respective first ground-support locations;

the vertical support and lift system adapted to support the gantry in atleast one operational vertical position above the respective bridge spansupport-surfaces of the piers, the at least one position correspondingto disembarking plane in which the leg portions are extended by thecontrol system from a stowed position on the pre-installation conveyancesystem to an extent sufficient for the gantry assembly to self-liftoffthe pre-installation conveyance system onto the first ground-supportlocations; and

controlling the vertical support and lift system such that the gantryassembly self-lifts off the pre-installation conveyance system onto thefirst ground support locations.

It is to be understood that the vertical support and lift system ispowered to lift a suitable load and that a control system used forcontrolling the vertical support and lift system is at least adapted tocontrol the vertical height of the gantry.

According to another embodiment, a gantry assembly is adapted to beoperatively associated a gantry conveyance system supported by thegantry and a ground conveyance system, the ground conveyance systemincluding a support portion for supporting the bridge span, the gantryconveyance system operatively associated with a control system and apower system and adapted for conveying a bridge span in a horizontaltransport plane relative to the gantry assembly over distance sufficientto transfer a load corresponding to the weight of the bridge span fromthe gantry conveyance system to the support portion of the groundconveyance system from the support portion of the ground conveyancesystem to the gantry conveyance system.

The gantry conveyance system including two conveyable separatelylocatable bridge span support means e.g. a suspension means, forsupporting the bridge span, the gantry assembly and the support meansoperatively associated with a lift system (e.g. a winch), the liftsystem adapted for raising a bridge from the piers into the horizontaltransport plane and lowering a bridge span onto the piers from ahorizontal transport plane.

Additional embodiments of the methods are now summarized.

Optionally, as described above, the ground engaging vertical support andlift system comprises a first vertical support assembly for supportingthe gantry proximal to one end thereof and a second vertical supportassembly for supporting the gantry proximal to the opposite end thereof,each vertical support assembly comprising leg portions, a gantryconnection portion for connecting a leg portion to the gantry and aground engaging portion for supporting a leg portion on a firstground-support location, the vertical support and lift system adapted tobe operatively associated with a power system and a control system, thevertical support and lift system, power system and control systemadapted for controlling the linear vertical distance between the groundengaging portion of a leg portion and the gantry so as control thevertical height of the gantry.

Optionally, as described above, the distance between the lateralperimeters of the pre-installation conveyance system is wider that thewidth of the gantry, the gantry assembly configured such that theground-engaging portions of the leg portions are suspended outside thelateral perimeters of the pre-installation conveyance system footprintarea in the stowed position so as to provide lateral clearance for theground engaging portions to be extended into installation positions onthe first ground-support locations and for the pre-installation systemto be removed from above the existing bridge span.

Optionally, the method further comprises:

bringing a ground conveyance system into horizontal alignment withload-bearing second ground-support locations in which the groundconveyance system is positioned on a path defined by a portion of atrain track contiguous with the train track overlying the existingbridge span, the gantry conveyance system comprising a track and atleast one vehicle conveyable on the track, the at least one vehicleadapted to be operatively associated with the bridge span connectionsystem for suspending the bridge span from the at least one vehiclebeneath the gantry, the gantry conveyance system and bridge spanconnection system adapted for supporting the weight of a bridge spanbeneath the gantry for conveyance in a substantially horizontal plane onthe track along at least a portion of the length of the gantry, thegantry assembly and/or the gantry conveyance system defining a vehicleposition limit that delimits a maximum horizontal travel distance thatthe at least one vehicle can travel in the horizontal transport planewhen supporting a load comprising at least a portion of the weight ofthe existing bridge span, a vehicle position limit and/or the pathdefining a threshold horizontal displacement distance which is at leastsufficient to transfer load support from the gantry conveyance system tothe ground conveyance system;

adjusting the height of the gantry, if and as necessary, connecting thebridge span connection system between the bridge span and the gantryconveyance system, such that the bridge span is prepared to be suspendedfrom the gantry conveyance system when the gantry is lifted by thevertical support and lift system into the at least one horizontaltransport plane;

Controlling the vertical support and lift system to raise train bridgespan into the least one horizontal transport plane;

Using the gantry conveyance system to convey the bridge span into atleast one load transferring position overlying the support portion ofthe ground conveyance system, the load transferring position adapted fortransferring a load corresponding to the weight of the bridge span fromthe gantry conveyance system to the ground conveyance system; and

Transferring a load corresponding to the weight of the bridge span, fromthe gantry conveyance to the ground conveyance system, the controlsystem controllable to lower the existing bridge span onto the supportportion of the ground conveyance system.

Optionally, the method further comprises:

Using the gantry conveyance system to convey the bridge span towards avehicle position limit into a load-transferring first position overlyingthe ground conveyance system;

Transferring the load attributable to a forward end portion of thebridge span to the ground conveyance system;

Using the ground conveyance system in combination with the gantryconveyance system to convey the train bridge span beyond the vehicleposition limit to a load transferring second position in which the loadattributable to a rearward end portion of the existing bridge span istransferable to the ground conveyance system; and

Transferring a load attributable to the rearward end-portion of theexisting bridge span to the ground conveyance system, such that theexisting bridge is removable from a site of replacement of an existingbridge span.

Optionally, the method further comprises:

Using a second ground conveyance system to convey a replacement bridgespan into alignment with load bearing third ground-support locationscorresponding to portions of a train track leading to the rearward pierin which at least a forward end the replacement bridge span ispositioned under the gantry conveyance system;

Transferring a load attributable to at least a forward end portion ofthe replacement train-bridge span to the gantry conveyance system and abridge span connection system;

Using the gantry conveyance system and the second ground conveyancesystem to convey the replacement bridge span into horizontal alignmentwith a third ground-support location in which a rearward end portion ofthe replacement bridge span is positioned under the gantry conveyancesystem and transferring a load attributable to the rearward end portionof the replacement train-bridge span to the gantry conveyance system andbridge span connection system;

Using the gantry conveyance system and bridge span connection system toconvey the replacement bridge span into horizontal alignment with bridgespan support-surfaces of the first and second piers;

Using the control system to lower the replacement bridge span onto thebridge span support-surfaces of the first and second piers.

Optionally, the method further comprises:

Removing the bridge span connection system from the replacement bridgespan.

Adjusting the height of the gantry, as necessary, conveying apost-installation conveyance system including a support bed configuredto support the gantry installation under the gantry installation andusing the lift system to lift the ground engaging portions of thevertical support system from the first ground-support locations suchthat the weight of the gantry installation is transferred onto thepost-installation conveyance system;

Transporting the gantry installation away the replacement bridge span.

Optionally, the method is executed according to a schedule thataccommodates a scheduled maximum delay of train traffic across the trainbridge, the path at least sufficient of sufficient length to convey theexisting bridge span to a site for off-loading the existing bridge span.

Optionally, a combined footprint of the pre-installation conveyancesystem and gantry assembly supported thereon is accommodated by anexisting train route for bringing the gantry assembly onto a gantryinstallation worksite including through or via any train tunnel, traintrack or train station along the existing train route.

Optionally, a combined footprint of the post-installation conveyancesystem and gantry assembly supported thereon is accommodated by anexisting train route for bringing the gantry assembly off a gantryinstallation worksite and optionally onto a new gantry installationworksite including through or via any train tunnel, train track or trainstation along the existing train route.

Optionally, the pre-installation conveyance system comprises a forwardrail car which supports a forward end portion of the gantry installationand a rearward rail car which supports a rearward end of the gantryinstallation, and wherein the combined footprint area of the rail carsis approximately 10 ft. wide by 130 ft. long.

Optionally, each vertical support assembly includes a gantry connectionportion and a pair of laterally separated leg portions havingground-engaging portions adapted for supporting the gantry on the groundat the load-bearing first ground-support locations, the gantryconnection portion preferably including an outrigger portion configuredto laterally displace the leg portions of the vertical supportassemblies from lateral perimeters of the gantry, the lateraldisplacement accommodating passage of bridge span between the legportions of the first and second vertical support assemblies when an abridge span is transported into a load transferring position, theoutrigger portion preferably configured to position the leg portions ofa vertical support assembly perpendicularly to the gantry outside atleast the lateral perimeters of the pre-installation conveyance systemwith the ground engaging leg portions preferably overlying the firstground-support locations such that the gantry assembly is adapted to beinstalled when the gantry assembly is conveyed into horizontal alignmentwith the first ground-support locations and the lift system extends theleg portions thereby lowering the ground engaging portions of the legportions onto the first ground-support locations to lift the gantry offthe pre-installation conveyance system, the at least one verticalposition including a vertical position of a height sufficient for thepre-installation conveyance system to be moved under the gantryassembly.

Optionally, the bridge span connection system is a system of one morestraps operatively connected to the gantry conveyance system, andadapted to suspend a bridge span beneath the gantry in a horizontalorientation for transport in the at least one horizontal transportplane, the at least one horizontal transport plane having a lower limitoptionally defined by a lower limit of the transported bridge span orthe bridge span support surface of the ground conveyance system.

Optionally, the ground conveyance system is adapted to be positioned onload-bearing second ground-support locations in the vicinity of thebridge-span support surface of the first pier, the ground conveyancesystem adapted to be driven on a path preferably defined by a traintrack, the path defining a horizontal displacement distance whichextends the forward horizontal vehicle position limit of the tracksystem on one side of the gantry by a distance sufficient to transferfull load support from the gantry conveyance system to the groundconveyance system, the ground conveyance system including a supportportion for supporting the weight of a bridge span, wherein the verticalsupport system and lift system are adapted to raise the gantry to aheight in which the lower limit of the first horizontal transport planeis above and clears the support portion of the ground conveyance system,such that the train bridge span can be conveyed by the gantry conveyancesystem into horizontal alignment with a forward vehicle position limitoverlying a support surface of the ground conveyance system, such thatthe bridge span can be received for support on the support surface ofthe ground conveyance system for conveyance through the horizontaldisplacement distance, optionally using the lift system to lower thebridge span on the ground conveyance system.

Optionally, the gantry conveyance system and bridge span connectionsystem are adapted to support the bridge span from points of suspensionon both sides of the gantry.

Optionally, the gantry conveyance system comprises two separatelylocatable vehicles, each respective vehicle conveyable along the gantryto a respective horizontal vehicle position limit and to a relativehorizontal position limit defined by the relative position of thevehicles on either end of the gantry, separation of the vehicles towardsthe horizontal vehicle displacement limits adapted to suspend the bridgespan from both ends of the gantry, each vehicle operatively connected toa spreader structure, the spreader structure, oriented transversely withrespect to the longitudinal axis of the gantry for distancing two pointsof suspension of the bridge span from the center of gravity of avehicle, the spreader structure thereby configured to suspend the bridgespan from two sides of the gantry.

Optionally, the bridge span connection system comprises straps, each endof spreader structure displaced sufficiently from center of gravity ofthe vehicle to define a line of sight between a respective end of thespreader structure and a point of contact or connection of the bridgespan connection system to the bridge span, each end of the spreaderstructure operatively associated with a connector for connecting astrap.

Optionally, the gantry conveyance system includes a self-propelledforward vehicle and a self-propelled rearward vehicle riding on thetrack system and wherein the ground conveyance system comprises aforward rail car and a rearward rail car, each rail car having a bridgespan support bed, wherein in operation:

the existing bridge span is raised into the at least one horizontaltransport plane by actuation of the vertical support and lift system andtransported in a horizontal plane by the forward vehicle and rearwardvehicle until the forward vehicle approaches a forward vehicle positionlimit in which the existing bridge span is positioned above the supportbed of the forward rail car, and wherein a portion of the loadattributable to the forward end portion of the existing bridge span isthen transferred onto the forward rail car, preferably by using the liftsystem to lower the gantry; and

wherein the existing train bridge span is then conveyed toward a fullground support position with at least partial support from the forwardrail car supporting a forward end portion of the bridge span and therearward vehicle supporting a rearward end portion of the bridge spanuntil the rearward end portion of the bridge span is positioned abovethe support bed of the rearward rail car and wherein the load is thentransferred onto a support bed of the rearward rail car preferably byusing the lift system to lower the gantry.

Optionally, the second ground conveyance system includes a forward railcar and rearward rail car, comprising:

Using the second ground conveyance system to convey a replacement bridgespan into alignment with load bearing third ground-support locations inwhich a forward end the replacement bridge span is positioned under theforward vehicle;

Transferring a load corresponding to a forward end portion of thereplacement bridge span to the forward vehicle and a bridge spanconnection system;

Using the gantry conveyance system and the second ground conveyancesystem to convey the replacement bridge span into horizontal alignmentwith a third ground-support location in which a rearward end portion ofthe replacement bridge span is positioned under the rearward vehicle andtransferring a load attributable to the rearward end portion of thereplacement train-bridge span to the rearward vehicle and bridge spanconnection system;

Using the gantry conveyance system and bridge span connection system toconvey the replacement bridge span into horizontal alignment with bridgespan support-surfaces of the first and second piers;

Using the lift system to lower the replacement bridge span onto thebridge span support-surfaces of the first and second piers.

Optionally, the method further comprises:

Removing the bridge span connection system from the replacement bridgespan;

Adjusting the height of the gantry as necessary, conveying apost-installation conveyance system including a support bed configuredto support the gantry installation under the gantry installation andusing the lift system to lift the ground engaging portions of thevertical support system from the first ground-support locations suchthat the weight of the gantry installation is transferred onto thepost-installation conveyance system.

Optionally, the lift system is a hydraulic jack system wherein the legportions of the first and second vertical support assemblies arehydraulic legs.

A method of organizing installation or replacement of a train bridgespan of the type which spans and is supported by two piers (25) of atrain bridge, each pier having and a bridge span support-surface (22),the method comprising:

using a pre-installation conveyance system (27) including at least onerail car to convey a gantry assembly, supported in a horizontalposition, into horizontal alignment with a plurality of load-bearingfirst ground-support locations;

the gantry assembly comprising a gantry and a ground-engaging verticalsupport and lift system, the vertical support and lift systemoperatively associated with a control system and including leg portions,each leg portion having a ground engaging portion for supporting the legportions on respective first ground-support locations;

the vertical support and lift system adapted to support the gantry in atleast one operational vertical position above the respective bridge spansupport-surfaces of the piers, the at least one position correspondingto disembarking plane in which the leg portions are extended by thecontrol system from a stowed position on the pre-installation conveyancesystem to an extent sufficient for the gantry assembly to self-liftoffthe pre-installation conveyance system onto the first ground-supportlocations; and

controlling the vertical support and lift system such that the gantryassembly self-lifts off the pre-installation conveyance system onto thefirst ground support locations.

Optionally, the gantry assembly is adapted to be operatively associatedwith a gantry conveyance system supported by the gantry and a groundconveyance system, the ground conveyance system including a supportportion for supporting the bridge span, the gantry conveyance systemoperatively associated with a control system and a power system andadapted for conveying a bridge span in a horizontal transport planerelative to the gantry assembly over distance sufficient to transfer aload corresponding to the weight of the bridge span from the gantryconveyance system to the support portion of the ground conveyance systemfrom the support portion of the ground conveyance system to the gantryconveyance system, the gantry conveyance system including two conveyableseparately locatable suspension means for supporting the bridge span,the gantry assembly and the support means operatively associated with alift system, the lift system adapted for raising a bridge from the piersinto the horizontal transport plane and lowering a bridge span onto thepiers from a horizontal transport plane.

Optionally the method is executed to a schedule that accommodates ascheduled maximum delay of train traffic across the train bridge, thepath at least sufficient of sufficient length to convey the existingbridge span to a site for off-loading the existing bridge span.

Optionally, the combined footprint of the pre-installation conveyancesystem and gantry assembly supported thereon is accommodated by anexisting train route for bringing the gantry assembly onto a gantryinstallation worksite including through or via any train tunnel, traintrack or train station along the existing train route.

Optionally, a combined footprint of the post-installation conveyancesystem and gantry assembly supported thereon is accommodated by anexisting train route for bringing the gantry assembly off a gantryinstallation worksite and optionally onto a new gantry installationworksite including through or via any train tunnel, train track or trainstation along the existing train route.

Optionally, the pre-installation conveyance system comprises a forwardrail car which supports a forward end portion of the gantry installationand a rearward rail car which supports a rearward end of the gantryinstallation. Optionally, the combined footprint area of the rail carsis approximately 5 to 10 ft. wide by 130 ft. long.

Optionally, as described above, each vertical support assembly includesa gantry connection portion and a pair of laterally separated legportions having ground-engaging portions adapted for supporting thegantry on the ground at the load-bearing first ground-support locations,the gantry connection portion preferably including an outrigger portionconfigured to laterally displace the leg portions of the verticalsupport assemblies from lateral perimeters of the gantry, the lateraldisplacement accommodating passage of bridge span between the legportions of the first and second vertical support assemblies when an abridge span is transported into a load transferring position, theoutrigger portion preferably configured to position the leg portions ofa vertical support assembly perpendicularly to the gantry outside atleast the lateral perimeters of the pre-installation conveyance systemwith the ground engaging leg portions preferably overlying the firstground-support locations such that the gantry assembly is adapted to beinstalled when the gantry assembly is conveyed into horizontal alignmentwith the first ground-support locations and the lift system extends theleg portions thereby lowering the ground engaging portions of the legportions onto the first ground-support locations to lift the gantry offthe pre-installation conveyance system, the vertical positions includinga vertical position of a height sufficient for the pre-installationconveyance system to be removed from or re-positioned from originalsupport locations beneath the gantry assembly.

Optionally, as described above, the bridge span connection system is asystem of one more straps operatively connected to the gantry conveyancesystem, and adapted to suspend a bridge span beneath the gantry in ahorizontal orientation for transport in the at least one horizontaltransport plane, the at least one horizontal transport plane having alower limit optionally defined by a lower limit of the transportedbridge span or the bridge span support surface of the ground conveyancesystem.

Optionally as described above, the ground conveyance system is adaptedto be positioned on load-bearing second ground-support locations in thevicinity of the bridge-span support surface of the first pier, theground conveyance system adapted to be driven on a path preferablydefined by a train track, the path defining a horizontal displacementdistance which extends the forward horizontal vehicle position limit ofthe track system on one side of the gantry by a distance sufficient totransfer full load support from the gantry conveyance system to theground conveyance system, the ground conveyance system including asupport portion for supporting the weight of a bridge span, wherein thevertical support system and lift system are adapted to raise the gantryto a height in which the lower limit of the first horizontal transportplane is above and clears the support portion of the ground conveyancesystem, such that the train bridge span can be conveyed by the gantryconveyance system into horizontal alignment with a forward vehicleposition limit overlying a support surface of the ground conveyancesystem, such that the bridge span can be received for support on thesupport surface of the ground conveyance system for conveyance throughthe horizontal displacement distance, optionally using the lift systemto lower the bridge span on the ground conveyance system.

Optionally, the gantry conveyance system and bridge span connectionsystem are adapted to support the bridge span from points of suspensionon both sides of the gantry.

Optionally, the gantry conveyance system comprises two separatelylocatable vehicles, each respective vehicle conveyable along the gantryto a respective horizontal vehicle position limit and to a relativehorizontal position limit defined by the relative position of thevehicles on either end of the gantry, separation of the vehicles towardsthe horizontal vehicle displacement limits adapted to suspend the bridgespan from both ends of the gantry, each vehicle operatively connected toa spreader structure, the spreader structure, oriented transversely withrespect to the longitudinal axis of the gantry for distancing two pointsof suspension of the bridge span from the center of gravity of avehicle, the spreader structure thereby configured to suspend the bridgespan from two sides of the gantry.

Optionally, the bridge span connection system comprises straps, each endof spreader structure displaced sufficiently from center of gravity ofthe vehicle to define a line of sight between a respective end of thespreader structure and a point of contact or connection of the bridgespan connection system to the bridge span, each end of the spreaderstructure operatively associated with a connector for connecting astrap.

Optionally, the gantry conveyance system includes a hydraulicallypowered forward vehicle and a hydraulically powered rearward vehicleriding on the track system and wherein the ground conveyance systemcomprises a forward rail car and a rearward rail car, each rail carhaving a bridge span support bed, wherein in operation:

the existing bridge span is raised into the at least one horizontaltransport plane by actuation of the vertical support and lift system andtransported in a horizontal plane by the forward vehicle and rearwardvehicle until the forward vehicle approaches a forward vehicle positionlimit in which the existing bridge span is positioned above the supportbed of the forward rail car, and wherein a portion of the loadattributable to the forward end portion of the existing bridge span isthen transferred onto the forward rail car, preferably by using thevertical support and lift system to lower the gantry; and

wherein the existing train bridge span is then conveyed toward a fullground support position with at least partial support from the forwardrail car supporting a forward end portion of the bridge span and therearward vehicle supporting a rearward end portion of the bridge spanuntil the rearward end portion of the bridge span is positioned abovethe support bed of the rearward rail car and wherein the load is thentransferred onto a support bed of the rearward rail car preferably byusing the lift system to lower the gantry.

Optionally, the second ground conveyance system includes a forward railcar and rearward rail car, comprising:

Using the second ground conveyance system to convey a replacement bridgespan into alignment with load bearing third ground-support locations inwhich a forward end the replacement bridge span is positioned under theforward vehicle;

Transferring a load corresponding to a forward end portion of thereplacement bridge span to the forward vehicle and a bridge spanconnection system;

Using the gantry conveyance system and the second ground conveyancesystem to convey the replacement bridge span into horizontal alignmentwith a third ground-support location in which a rearward end portion ofthe replacement bridge span is positioned under the rearward vehicle andtransferring a load attributable to the rearward end portion of thereplacement train-bridge span to the rearward vehicle and bridge spanconnection system;

Using the gantry conveyance system and bridge span connection system toconvey the replacement bridge span into horizontal alignment with bridgespan support-surfaces of the first and second piers; and

Using the vertical support and lift system to lower the replacementbridge span onto the bridge span support-surfaces of the first andsecond piers.

According to one embodiment, a system for removal or placement of atrain bridge-span of the type which spans and is supported by two piers,is characterized in that it comprises;

A lift system;

A gantry assembly comprising a gantry and a vertical support system forsupporting the gantry, the gantry assembly adapted to be transported ina horizontal position to a site for placement or removal of a bridgespan by a pre-installation conveyance system including at least one railcar;

The gantry assembly adapted to be operatively associated with the liftsystem, the lift system adapted to raise the bridge span from the piersinto a horizontal transport plane and to lower a bridge span from ahorizontal transport plane onto the piers;

the vertical support system including leg portions having groundengaging portions adapted to be supported on first ground supportlocations;

the gantry assembly adapted to support a gantry conveyance system, thegantry conveyance system adapted to cooperate with a load-bearing groundconveyance system including a support portion for supporting the bridgespan, the gantry conveyance system operatively associated with a bridgespan support system which provides at least two points of support forsupporting a bridge span from two respective positions on a bridge spanproximal to the end portions of the bridge span;

the gantry conveyance system adapted for horizontally conveying a bridgespan in a horizontal transport plane relative to the gantry assemblyover distance sufficient to transfer a load corresponding to the weightof a bridge span, in stages onto the support portion of a groundconveyance system;

the vertical support system and lift system adapted for supporting abridge span from the first ground-support locations in at least oneoperational vertical position above the respective bridge spansupport-surfaces of the piers, the at least one operational verticalposition corresponding to at least one horizontal transport plane and toa disembarking plane in which the leg portions are extendable from astowed position on the pre-installation conveyance system to an extentsufficient for the gantry assembly to self-liftoff the pre-installationconveyance system onto the first ground support locations.

Optionally, the bridge span support system is a bridge span suspensionsystem. Optionally, the bridge span suspension system comprises loadbearing straps attached between the gantry conveyance system and thebridge span.

The bridge span support system is a two point support system supportingthe bridge span in relation to gantry conveyance system to enable tobridge span to carried by the gantry conveyance system bothindependently and together with the ground conveyance system.

According to yet another aspect the invention is directed to the use ofa gantry assembly installation to remove and install a bridge span, forexample in accordance with any method or steps of a method hereindefined or together with any system or any parts of a system as hereindefined.

According to yet another aspect the invention is directed to the use ofa gantry assembly to remove and install a bridge span, for example inaccordance with any method or steps of a method herein defined ortogether with any system or any parts of a system as herein defined.

According to yet another aspect the invention is directed to the use ofa system as herein defined to remove and install a bridge span, forexample in accordance with any method or steps of a method hereindefined.

OTHER EMBODIMENTS

A vertically-adjustable gantry assembly installation adapted for removalor placement of a train bridge-span of the type which spans and issupported by two piers, comprising:

A gantry assembly positioned on load-bearing first ground-supportlocations, the gantry assembly comprising a gantry and a ground-engagingvertical support and lift system, the gantry assembly adapted tooperatively associated with a gantry conveyance system;

the vertical support and lift system adapted for supporting a combinedweight of the gantry and a bridge span in at least one operationalvertical position above respective bridge span support-surfaces of thepiers including a position corresponding to a disembarking plane inwhich the leg portions are extended from a stowed position to an extentsufficient for the gantry assembly to self-liftoff the pre-installationconveyance system onto the first ground-support locations to effect thegantry assembly installation.

A vertically-adjustable gantry assembly installation adapted for removalor placement of a train bridge-span of the type which spans and issupported by two piers, comprising:

A gantry assembly positioned on load-bearing first ground-supportlocations, the gantry assembly comprising a gantry and a ground-engagingvertical support and lift system, the gantry assembly adapted tooperatively associated with a gantry conveyance system adapted tosupport the weight of the bridge span and a ground conveyance system;

the vertical support and lift system including leg portions havingground engaging portions and a gantry connection portion including anoutrigger portion, the vertical support and lift system adapted forsupporting a combined weight of the gantry and a bridge span in at leastone operational vertical position above respective bridge spansupport-surfaces of the piers including a position corresponding to ahorizontal transport plane in which the bridge span is conveyed by thegantry conveyance system along at least a portion of gantry.

A vertically-adjustable gantry assembly installation adapted for removalor placement of a train bridge-span of the type which spans and issupported by two piers, comprising:

A gantry assembly positioned on load-bearing first ground-supportlocations, the gantry assembly comprising a gantry and a ground-engagingvertical support and lift system, the gantry assembly adapted tooperatively associated with a gantry conveyance system and a groundconveyance system;

the vertical support and lift system adapted for supporting a combinedweight of the gantry and a bridge span in at least one operationalvertical position above respective bridge span support-surfaces of thepiers including a position corresponding to a disembarking plane inwhich the gantry assembly is adapted to self-liftoff thepre-installation conveyance system onto the first ground-supportlocations to effect the gantry assembly installation, the verticalsupport and lift system including leg portions, the leg portionsincluding ground engaging portions, the ground engaging portionsincluding overhang portions of a ground support structure, the legportions operatively associated with an alignment system for aligningthe overhang portions with ground-support portions of the ground supportstructure.

A gantry assembly for removal or placement of a train bridge-span of thetype which spans and is supported by two piers, comprising:

A gantry;

A ground-engaging vertical support and lift system;

the vertical support and lift system including:

a load bearing first vertical support assembly operatively connected tothe gantry proximalto a first end thereof; and

a load-bearing second vertical support assembly operatively connected tothe gantry proximal to a second end thereof;

the gantry assembly adapted to support a gantry conveyance system, thegantry conveyance system adapted to be operatively associated with abridge span support system for supporting the bridge span from at leasttwo positions on the bridge span proximal to the ends of the bridgespan;

the vertical support and lift system adapted for supporting a combinedweight of the gantry and a bridge span in at least one operationalvertical position above the respective bridge span support-surfaces ofthe piers including at least one position corresponding to a horizontaltransport plane.

Optionally, each vertical support assembly includes at least one legportion having a ground engaging portion and a gantry connection portionfor connecting the leg portions to the gantry, the gantry connectionportion including an outrigger portion, the vertical support and liftsystem including or adapted to be operatively associated with a powersystem and a control system to vary the linear vertical distance betweenthe ground engaging portion of a leg portion and the gantry to controlthe vertical height of the gantry.

Optionally, the at least one vertical position includes a positioncorresponding to a pre-installation conveyance system disembarkingplane.

Optionally, the vertical support and lift system is adapted to beoperatively associated with an alignment system for aligning the groundengaging portions of the leg portions with the first ground supportlocations.

A gantry assembly for removal or placement of a train bridge-span of thetype which spans and is supported by two piers, comprising:

A gantry;

A ground-engaging vertical support and lift system;

the gantry assembly configured to be transported in a horizontalposition to a site for placement or removal of a bridge span by apre-installation conveyance system including at least one rail car;

the vertical support and lift system including:

a load bearing first vertical support assembly operatively connected tothe gantry proximalto a first end thereof; and

a load-bearing second vertical support assembly operatively connected tothe gantry proximal to a second end thereof,

each vertical support assembly including at least one leg portion havinga ground engaging portion and a gantry connection portion for connectingthe leg portions to the gantry, the vertical support and lift systemadapted for supporting a combined weight of the gantry and a bridge spanfrom first ground-support locations in at least one operational verticalposition above the respective bridge span support-surfaces of the pier,at least one position corresponding to a disembarking plane in which theleg portions are extendable to an extent at least sufficient for thegantry assembly to self-liftoff the pre-installation conveyance systemonto the first ground-support locations.

A system for removal or placement of a train bridge-span of the typewhich spans and is supported by two piers, comprising:

A gantry assembly comprising a gantry and a ground-engaging verticalsupport and lift system, the gantry assembly adapted to be transportedin a horizontal position to a site for placement or removal of a bridgespan by a pre-installation conveyance system including at least one railcar;

the vertical support and lift system including:

a load bearing first vertical support assembly operatively connected tothe gantry proximalto a first end thereof; and

a load-bearing second vertical support assembly operatively connected tothe gantry proximal to a second end thereof,

each vertical support assembly including at least one leg portion havinga ground engaging portion and a gantry connection portion for connectingthe leg portions to the gantry, the vertical support and lift systemincluding or adapted to be operatively associated with a power systemand a control system to vary the linear vertical distance between theground engaging portion of a leg portion and the gantry to control thevertical height of the gantry, the vertical support and lift systemadapted for supporting a combined weight of the gantry and a bridge spanin operational vertical positions above the respective bridge spansupport-surfaces of the piers including at least one positioncorresponding to a horizontal transport plane, and a positioncorresponding to a disembarking plane in which the leg portions areextended by the power system from a stowed position on thepre-installation conveyance system to an extent at least sufficient forthe gantry assembly to self-liftoff the pre-installation conveyancesystem onto the first ground locations such that the pre-installationconveyance system can be removed from above the existing bridge spanbeneath the gantry assembly to effect a gantry installation;

a gantry conveyance system, supported by the gantry, adapted toindependently support the weight of a bridge span, and configured forconveying a bridge span in a substantially horizontal plane along atleast a portion of the length of the gantry (100), movement of bridgespan relative to the gantry via the gantry conveyance system (10)defining the horizontal transport plane, the gantry conveyance systemadapted to be operatively associated with a bridge span connectionsystem for suspending the bridge span from the at least one vehiclebeneath the gantry for conveyance in the horizontal transport plane,wherein the gantry conveyance system and bridge span connection systemare configured to provide conveyable suspension means for suspending thebridge span beneath the gantry from two positions on the bridge spanproximal to the end portions of the bridge span;

the gantry assembly and/or the gantry conveyance system definingsuspension means position limits that delimit a maximum horizontaltravel distance that the suspension means can travel in the horizontaltransport plane when supporting a load comprising at least a portion ofthe weight of the bridge span;

a load-bearing ground conveyance system including a support portion forsupporting a load comprising the weight of a bridge span, the groundconveyance system adapted to be transported on a path extending awayfrom a portion of train rail terminating at the bridge span, asuspension means position limit and/or the path accommodating conveyanceof the bridge through at least a threshold horizontal conveyancedistance required for transferring load support from the gantryconveyance system to the ground conveyance system and/or from the groundconveyance system to the gantry conveyance system.

Optionally, the vertical support and lift system is adapted to beoperatively associated with an alignment system for aligning the groundengaging portions of the leg portions with the first ground supportlocations.

Optionally, the ground engaging portion of the leg portions includeoverhang portions of a ground support structure, the alignment systemadapted to vertically align the overhang portions with ground-supportedportions of the ground support structure.

Optionally, wherein the ground support structure is a beam, optionally atie beam.

A system for removal or placement of a train bridge-span of the typewhich spans and is supported by two piers, comprising:

A gantry assembly comprising a gantry and a vertical support and liftsystem including leg portions having ground engaging portions adapted tobe supported on first ground support locations;

the gantry assembly adapted to be transported in a horizontal positionto a site for placement or removal of a bridge span by apre-installation conveyance system (27) including at least one rail car;

the gantry assembly adapted to support a gantry conveyance system, thegantry conveyance system adapted to cooperate with a load-bearing groundconveyance system, the gantry conveyance system including supportportions adapted to provide at least two points of support forsupporting the bridge span from two positions on the bridge spanproximal to the ends of the bridge span;

the vertical support and lift system adapted for supporting a combinedweight of the gantry and a bridge span from first ground-supportlocations in at least one operational vertical position above therespective bridge span support-surfaces of the piers at least oneoperational vertical position corresponding to position(s) including atleast one horizontal transport plane and a disembarking plane in whichthe leg portions are extendable from a stowed position on thepre-installation conveyance system to an extent sufficient for thegantry assembly to self-liftoff the pre-installation conveyance systemonto the first ground support locations to effect a gantry installation.

Optionally, the gantry assembly and/or the gantry conveyance systemdefine bridge span position limits that delimit a maximum horizontaltravel distance that the bridge span can be conveyed in the horizontaltransport plane when supported by the gantry conveyance system;

the ground conveyance system adapted to be transported on a pathextending away from a ground position adjacent to an edge of an existingbridge span, a bridge span position limit and/or the path accommodatingconveyance of the bridge through at least a threshold horizontalconveyance distance required for transferring load support from thegantry conveyance system to the ground conveyance system and/or from theground conveyance system to the gantry conveyance system.

A system for removal or placement of a train bridge-span of the typewhich spans and is supported by two piers, comprising:

A gantry assembly comprising a gantry and a vertical support and liftsystem including leg portions having ground engaging portions adapted tobe supported on first ground support locations;

the gantry assembly adapted to be transported in a horizontal positionto a site for placement or removal of a bridge span by apre-installation conveyance system including at least one rail car;

the gantry assembly adapted to support a gantry conveyance system, thegantry conveyance system adapted for horizontally conveying a bridgespan in a horizontal transport plane relative to the gantry assemblyover distance sufficient to transfer a load corresponding to the weightof the bridge span in stages onto a support portion of a groundconveyance system, the gantry conveyance system including a supportportion adapted to provide support for supporting the bridge span fromtwo positions on the bridge span, the positions proximal to therespective ends of the bridge span;

the vertical support and lift system adapted for supporting the gantryfrom first ground-support locations in at least one operational verticalposition above the respective bridge span support-surfaces of the piersat least one operational vertical position corresponding to position(s)including a disembarking plane in which the leg portions are extendablefrom a stowed position on the pre-installation conveyance system to anextent sufficient for the gantry assembly to self-liftoff thepre-installation conveyance system onto the first ground supportlocations.

Optionally, wherein the vertical support and lift system is adapted forsupporting the gantry in the horizontal transport plane.

Optionally, the gantry assembly and the support portion are operativelyassociated with a lift system, the lift system adapted for raising abridge from the piers into the horizontal transport plane and lowering abridge span onto the piers from a horizontal transport plane.

Optionally, the gantry conveyance system is adapted for horizontallyconveying a bridge span in a horizontal transport plane relative to thegantry assembly over distance sufficient to transfer a loadcorresponding to the weight of the bridge span in stages from a supportportion of a ground conveyance system to the gantry conveyance system.

A system for removal or placement of a train bridge-span of the typewhich spans and is supported by two piers, comprising:

A gantry assembly comprising a gantry, a vertical support system and alift system, the lift system adapted to raise the bridge span from thepiers into a horizontal transport plane and to lower a bridge span froma horizontal transport plane onto the piers, the vertical support systemincluding leg portions having ground engaging portions adapted to besupported on first ground support locations;

the gantry assembly adapted to be transported in a horizontal positionto a site for placement or removal of a bridge span by apre-installation conveyance system including at least one rail car;

the gantry assembly adapted to support a gantry conveyance system, thegantry conveyance system adapted to cooperate with a load-bearing groundconveyance system including a support portion for supporting the bridgespan, the gantry conveyance system operatively associated with a bridgespan support system adapted to provide at least two points of supportfor supporting a bridge span from two positions on the bridge spanproximal to the end portions of a bridge span;

the gantry conveyance system adapted for horizontally conveying a bridgespan in a horizontal transport plane relative to the gantry assemblyover distance sufficient to transfer a load corresponding to the weightof a bridge span, in stages onto the support portion of a groundconveyance system;

the vertical support system and lift system adapted for supporting abridge span from the first ground-support locations in at least oneoperational vertical position above the respective bridge spansupport-surfaces of the piers, the at least one operational verticalposition corresponding to at least one horizontal transport plane and toa disembarking plane in which the leg portions are extendable from astowed position on the pre-installation conveyance system to an extentsufficient for the gantry assembly to self-liftoff the pre-installationconveyance system onto the first ground support locations.

Optionally, the bridge span support system is a bridge span suspensionsystem.

Optionally, the bridge span suspension system comprises load bearingstraps attached between the gantry conveyance system and the bridgespan.

A method of organizing installation or replacement of a train bridgespan of the type which spans and is supported by two piers of a trainbridge, the method comprising:

using a pre-installation conveyance system including at least one railcar to convey a gantry assembly, supported in a horizontal position,into horizontal alignment with a plurality of load-bearing firstground-support locations;

the gantry assembly comprising a gantry and a ground-engaging verticalsupport and lift system including leg portions each having a groundengaging portion for supporting the leg portions on respective firstground-support locations;

the gantry assembly adapted to be operatively associated with a gantryconveyance system adapted for horizontally conveying a bridge span in ahorizontal transport plane relative to the gantry assembly over distancesufficient to transfer a load corresponding to the weight of the bridgespan in stages onto a support portion of a ground conveyance system;

the vertical support and lift system adapted supporting a combinedweight of the gantry and a bridge span in at least one operationalvertical position above the respective bridge span support-surfaces ofthe piers, the at least one position corresponding to:

the horizontal transport plane;

a disembarking plane, in which the gantry legs are extendable toself-lift the gantry assembly off the pre-installation conveyance systemto effect a gantry installation;

Controlling the vertical support and lift system to lift the gantryassembly off the pre-installation conveyance system to position thefirst and second vertical assemblies onto the first ground-supportlocations.

A system for removal or placement of a train bridge-span of the typewhich spans and is supported by two piers, comprising:

A gantry assembly comprising a gantry and a vertical support and liftsystem including leg portions having ground engaging portions adapted tobe supported on first ground support locations;

the gantry assembly adapted to be transported in a horizontal positionto a site for placement or removal of a bridge span by apre-installation conveyance system (27) including at least one rail car;

the gantry assembly adapted to support a gantry conveyance system, thegantry conveyance system adapted to cooperate with a load-bearing groundconveyance system, the gantry conveyance system including supportportions adapted to provide at least two points of support forsupporting the bridge span from two positions on the bridge spanproximal to the ends of the bridge span;

the vertical support and lift system adapted for supporting a combinedweight of the gantry and a bridge span from first ground-supportlocations in at least one operational vertical position above therespective bridge span support-surfaces of the piers at least oneoperational vertical position corresponding to position(s) including atleast one horizontal transport plane and a disembarking plane in whichthe leg portions are extendable from a stowed position on thepre-installation conveyance system to an extent sufficient for thegantry assembly to self-liftoff the pre-installation conveyance systemonto the first ground support locations to effect a gantry installation.

Optionally, the gantry assembly and/or the gantry conveyance systemdefine bridge span position limits that delimit a maximum horizontaltravel distance that the bridge span can be conveyed in the horizontaltransport plane when supported by the gantry conveyance system;

the ground conveyance system adapted to be transported on a pathextending away from a ground position adjacent to an edge of an existingbridge span, a bridge span position limit and/or the path accommodatingconveyance of the bridge through at least a threshold horizontalconveyance distance required for transferring load support from thegantry conveyance system to the ground conveyance system and/or from theground conveyance system to the gantry conveyance system.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described by way of example only withreference to the attached drawings, in which:

FIG. 1A is a perspective view of a gantry assembly installationaccording to one embodiment of the invention;

FIG. 1B is an enlarged view of one end of the gantry assemblyinstallation shown in FIG. 1A showing hydraulic power units and a remotecontrol system, and illustrating that the control system is controllingthe height of the legs, and movement of the vehicles belonging to thegantry conveyance system.

FIG. 2 is a side elevation view of an embodiment of a gantry assemblyincluding a gantry and a vertical support and lift system, supported ona pre-installation conveyance system in accordance with one embodimentof the invention;

FIG. 3 including FIGS. 3A-3H is a set of diagrammatic representations ofa system according to one embodiment of the invention showing sideelevations of a gantry assembly installation in use in various stages ofremoval and installation of a bridge span, as follows:

FIG. 3A is a simplified view a gantry assembly installation in which thegantry is in an initial lowered position, with opposing ends of anexisting bridge span strapped to independently locatable vehiclesbelonging to a gantry conveyance system;

FIG. 3B shows the gantry raised, with the existing bridge span strappedto independently locatable vehicles belonging to the gantry conveyancesystem;

FIG. 3C shows the existing bridge span having been moved forward by twovehicles belonging to the gantry conveyance system to aload-transferring position, in which the forward end portion of thebridge span is shown overlying both the rearward and the forward railcar of a ground conveyance system;

FIG. 3D shows an existing bridge span having moved forward into a fullground-support position with cooperative load support by the forwardrail car and the rearward vehicle;

FIG. 3E shows a replacement bridge span brought onto thirdground-support locations at the gantry assembly installation site by thetwo rail cars belonging to a second ground conveyance system, the twovehicles belonging to the gantry conveyance system positioned proximalto the rearward end of the gantry, the replacement bridge span beingpositioned in a load transferring position underneath the forwardvehicle of the gantry conveyance system;

FIG. 3F shows a replacement bridge span in a load-transferring positionadapted for full-gantry-support with the forward end of the replacementbridge span suspended by the forward vehicle of the gantry conveyancesystem and rearward end of the replacement bridge span lying underneaththe rearward vehicle of the gantry conveyance system;

FIG. 3G shows the gantry raised into a vertically elevated horizontaltransport plane, with the replacement bridge suspended via the bridgespan connection system by the forward and rearward vehicles of thegantry conveyance system, the forward and rearward vehicles havingconveyed the replacement bridge span into horizontal alignment with thebridge span support surfaces of the piers;

FIG. 3H shows the gantry lowered, with the replacement bridge spanseated on the bridge span support surfaces of the piers;

FIG. 4A is a schematic representation of one end of a gantry assemblyrepresenting a top elevation view of the gantry assembly with theoutrigger portions of a vertical support assembly in an installationposition;

FIG. 4B is a schematic representation of the end of a gantry assemblyrepresenting a top elevation view of the gantry assembly with theoutrigger and leg portions of a vertical support assembly in a stowedposition.

FIG. 5A is an elevation view of the end of a gantry assembly whensupported on a rail car of a pre-installation conveyance system showingthe outrigger and leg portions of a vertical support assembly in astowed position;

FIG. 5B is a view of the gantry assembly of FIG. 5A, showing theoutrigger and leg portions of the vertical support assembly in aninstallation position.

FIG. 5C is an elevation view of an end of a gantry assembly when liftedoff a rail car of a pre-installation conveyance system, with theoutrigger and leg portions of a vertical support assembly shown in aninstallation position and showing the legs extended to enable removal ofthe pre-installation conveyance system from beneath the gantry assembly.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

The invention will now be further described with reference to thedrawings.

Gantry Assembly

As shown in FIG. 1A, a gantry assembly 1 for removal or placement of atrain bridge-span of the type which spans and is supported by two pierscomprises a gantry 100 and a ground-engaging vertical support and liftsystem.

As shown in FIG. 2, the gantry assembly 1 is configured to betransported in a horizontal position to a site for placement or removalof a bridge span by a pre-installation conveyance system 27 including atleast one rail car 28.

The vertical support and lift system includes a load bearing firstvertical support assembly 2 operatively connected to the gantry 100proximalto a first end thereof and a load-bearing second verticalsupport assembly 29 operatively connected to the gantry 100 proximal toa second end thereof.

As best seen in FIG. 5A-5C, each vertical support assembly includes twoleg portions 20 having a ground engaging portion in the form of footportion 49 and a gantry connection portion 500 for connecting the legportions 20 to the gantry 100, the gantry connection portion 500including an outrigger portion 11 consisting of rotatable portions 11Aand 11B, the vertical support and lift system including or adapted to beoperatively associated with a power system (see FIG. 1B e.g. a hydraulicpower system), and a control system, to vary the linear verticaldistance between the ground engaging portion 49 of a leg portion 20 andthe gantry 100 to control the vertical height of the gantry 100. Thevertical support and lift system is adapted for supporting a combinedweight of the gantry and a bridge span in an operational verticalpositions above the respective bridge span support-surfaces of the piersincluding at least one position corresponding to a horizontal transportplane.

As best seen in FIGS. 4A, 4B, 5A and 5B, the outrigger portion 11(portions 11 A and 11B) of a gantry connection portion 500 together withthe leg portions 20 of a vertical support assembly are rotationallymounted with respect to a positionally-fixed portion 600 of the gantryconnection portion 500, for movement about a vertical axis perpendicularto the longitudinal axis of the gantry between a stowed position (FIG.4B) in which the outrigger portion and leg portion are rotated towardsthe gantry and a laterally extended ‘installation position’ illustratedin FIG. 4A. In the ‘stowed position’ (4B) a connection interface of theoutrigger portion 11, in the form of a flush plate 610, is securelyfastened, for example using a plurality of bolts, to a correspondinginterface of the positionally-fixed portion 600 of the gantry connectionportion 500, in the form of mating flush plate 615, to prevent rotationand accommodate full load support in the installation position. As bestseen in FIGS. 4A and 4B, a left side 11A and a right side 11B of theoutrigger portion 11 are independently hingedly-mounted via hinges 612to a positionally-fixed portion 600 of the gantry connection portion500.

System

According to one aspect of the invention, the gantry assembly 1 isadapted to cooperate with a power system, a control system, a gantryconveyance system including a track system, a bridge span connectionsystem, a first ground conveyance system and a second ground conveyancesystem. As shown in FIGS. 1A and 2, according to one embodiment of theinvention, the invention is directed to a system 200 for removal orplacement of a bridge span 6 of the type which spans and is supported byadjacent piers 25.

Control and Power Systems

As shown in FIG. 1B, according to one embodiment, two hydraulic powerunits 30 carried by the gantry 100 near the ends of the gantry 100,power both the vertical support and lift system and the vehicles of thegantry conveyance system. The power units are schematically shown as twosmall boxes without intending to comment on their relative size, adjunctparts or surface configuration. The user interface of the control systemis optionally localized in a single remote control unit, optionallyconfigured as a computer 32 in a robust tablet format with a joystick34. The control system may comprise a system of the type known as acomputer-aided remote lift (CARL—Lift Systems Inc.) system forcoordinating the vertical height of the gantry legs portions 20.Optionally, the same control unit also controls movement of the vehicles12 and 14 including power supplied to the vehicle hydraulics as well asthe direction of movement of the vehicles. Convenient settings enablethe joystick to either move the vehicles simultaneously or one or theother individually. A hydraulic power unit 30 is optionally allocated toeach vertical support assembly and a vehicle. For example, in terms ofcapacity is optionally capable of supplying approximately 3000 kN(kilonewtons) of lift force (e.g. at 2500 psi) to each vertical supportassembly (to each pair of leg portions).

Gantry Conveyance System

The gantry conveyance system 10 optionally comprises a pair ofseparately locatable, optionally hydraulically powered vehicles 12 and14, and a track system including a track 3. However, it will beappreciated that a single vehicle (in the sense of a horizontallyconveyable moving structural member to which a bridge span connectionsystem e.g. in the form of straps, is connected may be adapted tosupport a bridge span 6 at laterally spaced positions representingseparately conveyable/locatable points of suspension.

General design parameters affecting the choice of components of thegantry conveyance system 10 include the length of the gantry 100 and thelength of the respective vehicle(s), the length of the track 3, whethertrack 3 overhangs the gantry 100 or is horizontally displaceablerelative to the gantry 100, whether the connectors from which supportingrigging is suspended move horizontally in relation to a vehicle etc.

In general, the points of suspension are widely separated when the loadis fully supported by the gantry conveyance system. They are morenarrowly separated when the load is shared between a ground conveyancesystem and a gantry conveyance system. In principle, the gantryconveyance system and/or bridge span connection system and/or tracksystem can be adapted so that the distance between suspension means canbe both lengthened and shortened, in the course of operation.

As seen in FIG. 1A, the gantry conveyance system comprises twoindependently locatable vehicles 12 and 14, each respective vehicleconveyable along the gantry 100 to a respective vehicle position limitand to a relative vehicle position limit (the vehicle closest to the endof the gantry interposes and defines a position limit for the othervehicle) defined by the relative position of the vehicles on either endof the gantry 100, separation of the vehicles towards the vehicleposition limits adapted to suspend the bridge span from both ends of thegantry, as best seen in FIGS. 3B, 3F and 3G. As best seen in FIGS. 3Dand 3E, to transfer the bridge span from the gantry conveyance system tothe ground conveyance system, or vice versa, in a staged fashion, thevehicle separation is reduced. Analogously, where a first or secondground conveyance system consists of two rail cars, the distance betweenthe rail cars varies according to the stage of load transfer.

A load-bearing gantry conveyance system 10, supported by the gantry 100,is adapted to independently support the weight of the bridge span 6, andconfigured for conveying a bridge span 6 in a substantially horizontalplane along the length of the gantry 100, movement of bridge span 6relative to the gantry 100 via the gantry conveyance system 10 definingat least a first portion of a horizontal transport plane, the gantryconveyance system defining vehicle position limits in terms oftheoretical position maxima including a forward vehicle position limitproximal to one end (a forward end) of the gantry 100 and rearwardvehicle position limit proximal to the other end of the gantry 100.

According to one embodiment of the invention, the track 3 is secured tothe gantry and is preferably brought onto the bridge span replacementsite as part of the gantry assembly. Each vehicle (12, 14) comprises aspreader structure 16. The spreader structure 16 is orientedtransversely with respect to the longitudinal axis of the gantry 100 fordistancing two points of suspension of the bridge span from the centerof gravity of a vehicle (12, 14). The spreader structure 16 is therebyconfigured to suspend a bridge span (6, 36) from two sides of the gantry100.

Bridge spans vary in length. In this connection, it should beappreciated, that according to one embodiment of the invention describedin most detail herein, a gantry 100 of approximately 150 feet length maybe well suited to replace a bridge span (6, 36) of approximately 110feet in length. For example, the outrigger portions 11A and 11B, arepositioned at a distance from the end of the gantry (e.g. 10 feet fromeach end). The outrigger portions 11A and 11B block horizontal movementof the straps 7 in the process of conveyance of a bridge span in ahorizontal transport plane organized to transfer of the loadattributable to an end of the bridge span to or from the gantryconveyance system, since support points for the straps on the gantryconveyance system are above them. Therefore, while the size of thegantry, or the size track system (if more or less limiting) relative tothe length of the bridge span, defines absolute vehicle position limits,in the embodiment described, the position of the outrigger portionsrelative to the end of the gantry practically define the vehicleposition limits, since these positions may practically define relativevehicle positions determining the practical horizontal conveyancedistances required for load transfer to (or from) the ground conveyancesystem.

Therefore, in our example of a gantry of 150 in length with theoutrigger and leg portions spaced 10 feet from the end of gantry, theusable span of the track 3 may be 130 feet. Other factors that need toneed to be taken into account in this regard are support positions ofthe straps relative to the end of bridge span, the positioning of therail cars of the ground conveyance systems (limited by the ends of thetrack proximal to piers when an existing bridge span is lifted orabsent) and the positions of the support surfaces of the rail carsrelative to the positions of the gantry legs and the ends of the bridgespans. As a general rule of thumb, for removal of an existing bridgespan, at a stage when the rail cars are positioned next to one another,the bridge span support surface of forward rail car should at least beable to be approximately aligned with the forward end portion of thebridge span e.g. when the bridge span is positioned at the strapposition limit (a position that allows a rearward rail car to bepositioned behind the forward rail car). Similarly, during installationof a new bridge span, the support portion of the rear rail car should bealigned with a rearward end of the bridge span which may require thatthe support portion be horizontally aligned with the gantry leg (aposition that allows the forward rail car to be positioned in front ofthe rearward rail car).

Bridge Span Connection System

As best seen in FIGS. 1 and 5A-5C, according to one embodiment of theinvention, a bridge span support system takes the form of bridge spansuspension system. The bridge span suspension system takes the form of abridge span connection system which comprises straps 7 which may beoptionally looped to form slings.

Each end of the spreader structure 16 is displaced sufficiently from acenter of gravity of a vehicle (12, 14) to define a line of sightbetween a respective end of the spreader structure 16 and a point ofcontact or connection of the strap 7 to the bridge span, the spreaderstructure 16 optionally sized to exceed the width of the gantry 100(e.g. approx. 7 ft. plus)

Each end of the spreader structure 16 is operatively associated with aconnector for connecting a strap 7, the connector optionally in the formof a shackle 900 which may be rotationally mounted. The distance betweenthe connectors 900 is longer than the width of the gantry 100.Optionally, there are also connectors in the form of shackles(optionally rotationally-mounted) on the bridge span (not shown).Rotationally-mounted connectors 900 are optionally configured to permitthe sling arm to have play in plane parallel to longitudinal axis of thegantry (e.g. the connector is mounted for rotation about an axisperpendicular to the longitudinal axis of the gantry). The straps 7 areadapted to suspend a bridge span 6 beneath the gantry 100 (they are longenough so that the bridge span clears lower edge of gantry 100 whichdefines the upper limit of the horizontal transport plane, thehorizontal transport plane also having a lower limit defined by theheight of the support bed of the ground conveyance system).

Ground Conveyance System and Load Transfer

A load-bearing, ground engaging, first ground conveyance system 26 isadapted to be positioned on load-bearing second ground-support locationsin the vicinity of the bridge-span support surface of a forward pier 25,the ground conveyance system adapted to be driven on a path preferablydefined by a train track 24, the path defining a horizontal displacementdistance which extends a forward vehicle position limit on at least afirst side of the gantry 100 by a distance sufficient to transfer fullload support from the gantry conveyance system 10 to the groundconveyance system 26, the ground conveyance system 26 optionallyincluding a forward rail car 15 and rearward rail car 24 each having asupport portion 8 for supporting the weight of a bridge span 6. Thevertical support system and lift system is adapted to raise the gantry100 to a height in which the lower limit of the first horizontaltransport plane is above and clears the support portion 8 of the groundconveyance system 26, such that the train bridge span 6 can be conveyedby the gantry conveyance system 10 into horizontal alignment with a loadtransferring first position overlying support surfaces 8 of the groundconveyance system, and received for support on the support surfaces 8 ofthe ground conveyance system 26 for conveyance through a horizontaldisplacement distance, optionally using the vertical support and liftsystem to lower the bridge span 6 on the ground conveyance system 26.

The outrigger portion 11 is configured to laterally displace a legportion from lateral perimeters of the gantry 100, the lateraldisplacement accommodates passage of bridge span 6 between the legportions 20 of the first and second vertical support assemblies (2, 29)to enable load transfer from the gantry conveyance system to the groundconveyance system and vice versa.

As shown in FIGS. 3B to 3D the track 3 defines a forward vehicleposition limit A1 at a first end thereof and a rearward vehicle positionlimit A2 at a second end thereof. The ground conveyance system extendsthe horizontal transport plane so that the existing bridge span can betransferred from the gantry conveyance system to the ground conveyancesystem.

As shown in FIGS. 1 and 3B-3D a ground conveyance system comprising aforward rail car 15 and a rearward rail car 13 may be used inconjunction with the gantry conveyance system to convey an existingbridge span from a position above the piers with partial load supportfrom forward rail car 15 supporting a forward end of the existing bridgespan and partial load support from the rearward vehicle 13 supporting arearward end portion of the existing bridge span as described below.

As shown in FIGS. 1 and 3B-3D, the forward vehicle 14 is positioned onthe track in a position more proximate to the direction of removal ofthe existing bridge span 6 or installation of a replacement bridge span36, assuming the replacement bridge span 36 is launched from the samedirection to the one in which the existing bridge span is removed (i.e.from the opposite side of the gantry installation). It will beappreciated that a replacement bridge span may be launched from theopposite direction to the one in which the existing bridge span isremoved (i.e. from the same side of the gantry installation). It willalso be appreciated that installation of the gantry according to theparticular method described herein requires an existing bridge span orsurrogate to effect a gantry installation using a pre-installationconveyance system.

As seen in FIGS. 1A and 3E-3F, a load-bearing second ground conveyancesystem 21 is used to install a replacement bridge span 36, the secondground conveyance system 21 optionally including a forward rail car 17and rearward rail car 19 positioned on load-bearing third ground supportlocations in the vicinity of the bridge span support surface of pier 25,the forward rail car 17 positioned more proximal to the gantry assembly1.

Optionally, referring to FIGS. 3B to 3D, the track 3 is sufficientlylong to allow the forward end portion of the bridge span 6 to behorizontally aligned with the forward rail car 15 (in principle, theforward vehicle 14 need not be positioned as far forward as the forwardrail car 15) so that the load corresponding to the forward end of theexisting bridge span can be transferred from the forward vehicle to theforward rail car (having regard to relevant parameters such as theproximity of the point of attachment of the load-bearing strap(s) tothat end of the bridge span, relative positions of the first and secondground-support locations and the length of a vehicle and rail car).

Similarly, referring to FIGS. 3E to 3G, when a replacement bridge span36 is brought in from an opposite side of the gantry installation, therelative vehicle position limit of the forward vehicle 14 (taking inaccount the space on the track occupied by the rearward vehicle) allowsthe forward end portion of the replacement bridge span to be positionedsubstantially over the forward rail car 15 of the fourth conveyancesystem.

This length of track preferably allows the rearward end portion of abridge span to occupy a position over the rearward rail car 19 of thesecond ground conveyance system (taking into account the position of thestrap relative to the rearward end portion of the replacement bridgespan) so that the portion of the load attributable to the rearward endof the bridge span can be transferred from the rearward vehicle 12 tothe rearward rail car 19. Optionally, the usable portion of the track(defining vehicle position limits, as well as relative vehicle positionlimits i.e. the forward-most position of the rearward vehicle at theforward end of the track) may be approximately as long as the gantry andmay also be selected so that both the forward and rear rail cars can bepositioned underneath the track (it will be appreciated that relativeposition limits may be defined in terms the length of the forwardvehicle as well as a modest amount of space that is maintained betweenthe vehicles and between the forward vehicle position and the forwardposition limit). In this regard, it will be appreciated that the pointsof attachment of the straps proximal to an end portion of the bridgespan may be selected to be a certain distance from end of the bridgespan and that the bridge span may not be supported by a rail car at itsvery end.

The undersurface of the end of a bridge span 36 may be adapted forsupport on a rail car and/or on the bridge span support surfaces of theadjacent piers (see support portion 110—FIG. 3F).

Gantry Assembly Installation

By way of overview, as seen in FIGS. 1A and 1B, illustrating asimplified view of an embodiment of a gantry assembly installation, inaddition to a gantry assembly 1 described in detail below, such aninstallation optionally initially comprises at least a portion of agantry conveyance system 10 in the form of a track 3 belonging to atrack system supported by the gantry 100. Optionally, vehicle(s) 12 and14 may be supported on the track 3 when the gantry assembly 1 isinitially brought to the work site.

Furthermore, by way of overview, as best seen in FIGS. 1B and 3B, aground conveyance system 26 may be positioned at load bearing secondground-support locations proximal to the area overlying bridge spansupport surfaces 22 of piers 25. The bridge span support surfaces 22 ofthe piers 25 are typically below track level. A train track supportsubstructure of a bridge span 6 may typically have a series of beams 605connected at spaced junctions by struts 606 attached to the beams 605,the points of attachment of the struts to the beams exemplifying idealfirst, second and third load bearing ground-support locations for asupporting a gantry assembly installation.

The outrigger portion 11 is configured to position the leg portions 20perpendicularly to the gantry 100 outside the footprint area of thefirst ground conveyance system with the ground engaging leg portions 20overlying the first ground support locations such that when the gantry20, vertical support system (2,29) and lift system are operativelyconnected on the pre-installation conveyance system 27 and thepre-installation conveyance system 27 is transported into horizontalalignment with the first ground support locations, the lift system canextend the leg portions 20 thereby lowering the ground engaging portions49 of the leg portions onto the first ground support locations to liftthe gantry 100 off the pre-installation conveyance system 27 and effecta gantry installation, the vertical positions preferably including avertical position of a height sufficient for the pre-installationconveyance system to be removed from or repositioned beneath the gantryassembly installation, optionally, for re-use in or as or as part of aground conveyance system.

Optionally, the lift system of the vertical support and lift system is ahydraulic lift system. Optionally, each vertical support assembly (2,29) comprises two hydraulically extendible leg portions 20 whereby theeffective linear vertical distance between the ground engaging portionof each gantry leg portion and the gantry is adapted to be hydraulicallyvaried by the lift system. As described herein, the leg portions 20 areoptionally connected to the gantry 100 via an outrigger portion 11 suchthat the hydraulic leg portions 20 of the vertical support assemblies 2and 29 are laterally spaced apart to an extent accommodating extensionof the hydraulic legs to clear the lateral perimeters of thepre-installation conveyance system 27 to effect a gantry installationfrom off the pre-installation conveyance system (directly from aposition in which the gantry assembly 1 rests horizontally on thepre-installation conveyance system 27). Preferably, the leg portions 20of both vertical support assemblies 2 and 29 are laterally spaced apartto an extent permitting horizontal movement of the train bridge spans 6and 36 between them so as to enable the first and second groundconveyance systems to work from opposite sides of the gantry assembly 1.Optionally, this lateral distance is greater than the width of the railcars of the pre-installation conveyance system. It will be appreciatedthat the pre-installation and ground conveyance systems may share railcars. The numbering (i.e. first and second) used for the conveyancesystems is not meant to imply that rail cars must be allocated to oneconveyance system to the exclusion of another where sharing of rail carsis practical.

As best seen in FIGS. 5A and 5B the lateral perimeters of the gantryassembly footprint lie adjacent to the lateral perimeters of the supportbed 800 of a rail car 28 of the pre-installation conveyance system 27when the gantry assembly in supported on the pre-installation conveyancesystem 27 in the stowed position (5A). Optionally, the lateralperimeters of the gantry assembly lie within the lateral perimeters ofthe footprint area of the pre-installation conveyance system.

As best seen in FIGS. 1A and 1B and FIGS. 5A, 5B and 5C, leg portions 20of the vertical support assembly are adapted to be contracted orshortened by the lift system to occupy a compact configuration which isoptionally, beneath, at or above the height of the support platform ofthe pre-installation conveyance system when the gantry assembly issupported on the support platform in the stowed position. Extension ofthe gantry legs onto first ground locations may require the groundlocations to be adapted for load support. For example, a ground engagingload bearing support beam 9 may be installed over load supporting groundmaterial at ground locations corresponding to planned ground positionsof ground engaging portion(s) of the vertical support assemblies 2 and29. For example, the support beams in the form of beam assemblies 9 maybe supported on same ground material that the railroad ties aresupported on (e.g. track ballast comprising coarse aggregate; astructure associated with an adjacent bridge span etc.) under portionsof a train track leading respectively to and from an existing bridgespan. The support beams may be positioned to have a top-surface heightwhich provides load-bearing support to the under-surface of train-trackrails proximal to the first ground locations and may be supported atground locations at least partially formerly occupied by railroad ties.Thus installing a gantry assembly may involve advance removal ofexisting railroad ties and their replacement by a support beamoptionally in the form of middle portion 9B of beam assembly 9 (see FIG.1B).

It is noteworthy, that the lateral span of the outrigger portions 11,when rotated into the installation position, may exceed the lateraldimension of the railroad ties and the lateral span of supporting groundmaterial such that the ground engaging portions of leg portions 20 maybe positioned outside the available ground support area adjacent to thefirst ground locations. Particularly in the case of a train bridgespanned by multiple piers and bridge spans, replacement of a bridge spaninterposed between two others may require the first ground locations,optionally represented by the ends 9A and 9C of a beam assembly 9, tooverhang the available contiguous ground support material. The firstground locations may therefore be ‘manufactured’ and installed inadvance and/or as part of a gantry assembly installation process forexample by employing a three section beam as shown in FIG. 1B and bestseen in FIGS. 5A, 5B and 5C. In particular, end portions 9A and 9C ofthe support beam may be carried on site suspended from the gantry legsand then fastened on the middle portion 9B of support beam assembly 9 asseen in FIG. 1B. Portions 9A and 9C may be removed from ground engagingportions 49, fastened onto portion 9B (see FIG. 1B) and then groundengaging portions in the form of foot portions 49 are securely fastenedonto portions 9A and 9C respectively. Alternatively, when the gantryassembly is transported by a pre-installation conveyance system 27 intoalignment with first ground support locations, the gantry leg portions20 may be extended as particularly required to vertically align beamportions 9A and 9B with 9C with the aid of abutment portions 40 so thatbeam portions 9A and 9C can be fastened onto portion 9B while the weightof the gantry assembly is still borne by the pre-installation conveyancesystem. Accordingly, according to one embodiment of the invention, theleg portions of each vertical support assembly may include or may beadapted to be operatively associated with a vertical alignment means,for example, a descent-arresting abutment or stop means, for example alaterally projecting abutment portion 40 for aligning the overhangportions of a support beam 9A and 9C with a ground-supported portion 9B,for example, flange or plate 40 which extends laterally inwardly fromportions 9A and 9C in the course of being lowered. The overhang portions9A and 9C of an overhang ground support system are adapted to beattached e.g. by fasteners, to a ground-supported portion of a groundsupport structure in the form of beam portion 9B. These overhangportions 9A and 9B and are optionally adapted to be secured e.g. byfasteners, to the foot portions 49 of the leg portions 20. Theground-supported portion 9B is optionally similarly adapted. Therefore,the ground engaging portions 49 of the leg portions 20 are adapted foruse with an overhang ground-support system.

Method

According to one embodiment of the invention, the method comprises, asbest seen in FIGS. 2 and 5C:

using a pre-installation conveyance system 27 including at least onerail car 28 to convey a gantry assembly 1, preferably supported in asubstantially horizontal position, into horizontal alignment with aplurality of load-bearing first ground-support locations, wherein thegantry assembly 1 overlies an existing bridge span 6; and

controlling the vertical support and lift system to lift the gantryassembly 1 off the pre-installation conveyance system 27 to effect agantry assembly installation.

This makes it possible to remove or re-position rail cars 28, and asnecessary secure the ground engaging portions of the leg portion 20 tosupport surfaces e.g. tie beams 9, at the first ground-supportlocations.

Optionally, at least one component of the pre-installation conveyancesystem 27 e.g. rail cars are reused as part of a ground conveyancesystem 21 and/or 26. For re-use the position of the rail cars 28 mayneed to be adjusted to be positioned at second and/or third groundsupport locations. Alternatively they are removed from beneath thegantry assembly 1. Locomotive 770 may remain on-site to transport anexisting bridge span 6 away from the work site.

In connection with removing or repositioning the pre-installationconveyance system 27 from beneath the gantry 100, where the lateralperimeters of the pre-installation conveyance system 27 are wider thatthe gantry, the gantry assembly 1 is configured so that theground-engaging portions of the leg portions 20 are suspended outsidethe lateral perimeters of the pre-installation conveyance systemfootprint so as to provide lateral clearance for the ground engagingportions to be extended onto the first ground-support locations and forthe pre-installation system to be removed/repositioned from beneath thegantry 100. As described above with reference to FIGS. 4A-4B and 5A-5Cthis is accomplished, according to one embodiment of the invention, byrotating the outrigger portions 11A and 11B from a stowed position intoan installation position and securing the outrigger end plates 610 toanother portion of the gantry connection portion, for example a matingend plate portion 615, which is securely fixed to the gantry or at leastadapted to be securely fixed in a position to provide the necessarysupport and stability.

According to one embodiment of the method, defined in terms ofpositioning of vehicles 12 and 14 of the gantry conveyance system 10 andthe at the least one rail car of the ground conveyance system 26, it iskey that the gantry conveyance system 10 and bridge span connectionsystem are adapted for horizontally conveying a raised existing bridgespan in a horizontal transport plane over distance sufficient totransfer a load corresponding to the weight of the existing bridge span6 in at least one stage onto a support portion of a ground conveyancesystem 26.

The method further comprises (see FIGS. 3A and 3B):

bringing a ground conveyance system 26 into horizontal alignment withload-bearing second ground-support locations in which the groundconveyance system 26 is positioned on a path defined by a portion of atrain track contiguous with the train track overlying the existingbridge span;

adjusting the height of the gantry 100, if necessary, connecting thebridge span connection system in the form of straps 7 (optionally loopedto form a sling) between the bridge span 6 and the gantry conveyancesystem 10, such that the bridge span 6 is prepared to be suspended fromthe gantry conveyance system 10 when the gantry 100 is lifted by thevertical support and lift system into the at least one horizontaltransport plane;

Controlling the vertical support and lift system to raise train bridgespan 6 into the least one horizontal transport plane;

Using the gantry conveyance system 10 to convey the bridge span 6 intoat least one load transferring position overlying a support portion ofthe ground conveyance system (see FIG. 3C), the load transferringposition adapted for transferring a load corresponding to the weight ofthe bridge span from the gantry conveyance system 10 to the groundconveyance system 26; and

Transferring a load, corresponding to the weight of the bridge span 6,from the gantry conveyance 10 to the ground conveyance system 26(optionally vehicles 13 and 15), the control system controllable tolower the existing bridge span 6 onto the support portion 8 of theground conveyance system 26 (see FIG. 3D).

The latter steps, described in general terms may be accomplished,according to one embodiment of the method, as follows:

the gantry conveyance system 10 is used to convey the bridge span 6towards a vehicle position limit into a load-transferring first positionoverlying the ground conveyance system 26 to transfer the loadattributable to a forward end portion of the bridge span to the groundconveyance system 26, whereupon the ground conveyance system 26 incombination with the gantry conveyance system 10 are used to convey thetrain bridge span beyond the vehicle position limit to a loadtransferring second position in which the load attributable to arearward end portion of the existing bridge span is transferable to theground conveyance system and a load attributable to the rearwardend-portion of the existing bridge span 6 is then transferred to theground conveyance system 10, such that the existing bridge span 6 isremovable from the work site.

More particularly, the gantry conveyance system may include ahydraulically powered forward vehicle 14 and a hydraulically poweredrearward vehicle 12 riding on a track 3 of the track system and theground conveyance system may comprises a forward rail car 15 and arearward rail car 13, each rail car having a bridge span support bed 8,wherein in operation:

the existing bridge span 6 is raised into the at least one horizontaltransport plane by actuation of the vertical support and lift system andtransported in a horizontal plane by the forward vehicle 14 and rearwardvehicle 12 until the forward vehicle 14 approaches a forward vehicleposition limit in which the existing bridge span is positioned above thesupport bed of the forward rail car 15, whereupon a portion of the loadattributable to the forward end portion of the existing bridge span 6 isthen transferred onto the forward rail car 15, optionally by using thelift system to lower the gantry 100; and

wherein the existing train bridge span 6 is then conveyed toward a fullground support position with at least partial support from the forwardrail car 15 supporting a forward end portion of the bridge span 6 andthe rearward vehicle 12 supporting a rearward end portion of the bridgespan 6 until the rearward end portion of the bridge span is positionedabove the support bed of the rearward rail car 13, whereupon the load istransferred onto a support bed of the rearward rail car 13 preferably byusing the lift system to lower the gantry 100.

Replacing the existing bridge span 6, with a replacement bridge span 36,as shown in 3E to 3H, optionally involves the following general steps:

Using a second ground conveyance system 21 optionally comprising railcars 17 and 19 to convey a replacement bridge span 36 into alignmentwith load bearing third ground-support locations corresponding toportions of a train track leading to the rearward pier at which at leasta forward end the replacement bridge span 36 is positioned under thegantry conveyance system 10;

Transferring a load attributable to at least a forward end portion ofthe replacement train-bridge span 36 to the gantry conveyance system 10(e.g. vehicles 12 and 14) and a bridge span connection system includingstraps 7;

Using the gantry conveyance system 10 and the second ground conveyancesystem 21 (e.g. vehicle 19) to convey the replacement bridge span 36into horizontal alignment with a third ground-support location in whicha rearward end portion of the replacement bridge span 36 is positionedunder the gantry conveyance system and transferring a load attributableto the rearward end portion of the replacement train-bridge span to thegantry conveyance system 10 and the bridge span connection system;

Using the gantry conveyance system 10 and bridge span connection systemto convey the replacement bridge span 36 into horizontal alignment withbridge span support-surfaces 22 of the piers 25;

using the vertical support and lift system to lower the replacementbridge span 36 onto the bridge span support-surfaces 22 of the piers 25.

More particularly, the gantry conveyance system may include a forwardvehicle 14 and a rearward vehicle 12 riding on a track 3 and the groundconveyance system comprises a forward rail car 17 and a rearward railcar 19, each rail car having a bridge span support bed, wherein inoperation:

Using the forward rail car 17 and a rearward rail car 19 to convey areplacement bridge span 36 into alignment with load bearing thirdground-support locations in which a forward end the replacement bridgespan 36 is positioned under the forward vehicle 14;

Transferring a load corresponding to a forward end portion of thereplacement bridge span 36 to the forward vehicle 14 and the bridge spanconnection system;

Using the forward vehicle 14 in conjunction with the rearward rail car19 and the bridge span connection system to convey the replacementbridge span 36 into horizontal alignment with a third ground-supportlocation in which a rearward end portion of the replacement bridge span36 is positioned under the rearward vehicle 12 and transferring a loadattributable to the rearward end portion of the replacement train-bridgespan from the rearward rail car 19 to the rearward vehicle 12 and bridgespan connection system;

Using the forward vehicle 14 and rearward vehicle 12 in conjunction withthe bridge span connection system, to convey the replacement bridge span36 into horizontal alignment with bridge span support-surfaces of thefirst and second piers; and

Using the vertical support and lift system to lower the replacementbridge span onto the bridge span support-surfaces of the first andsecond piers.

Subsequently the bridge span connection system including straps 7 areremoved from the replacement bridge span 36; and

Again, adjusting the height of the gantry, as necessary, conveying apost-installation conveyance system including a support bed configuredto support the gantry installation under the gantry assemblyinstallation and using the lift system to lift the ground engagingportions 49 of the vertical support system from the first ground-supportlocations such that the weight of the gantry assembly 1 is transferredonto the post-installation conveyance system (not shown); and

transporting the gantry assembly 1 away from the replacement bridgespan.

Optionally, the method is executed according to a schedule thataccommodates a scheduled maximum delay of train traffic across the trainbridge (e.g. 6 to 16 hours), the path at least of sufficient length toconvey the existing bridge span to a site for off-loading the existingbridge span.

Optionally, a combined footprint of the pre-installation conveyancesystem 27 and gantry assembly 1 supported thereon is accommodated by anexisting train route for bringing the gantry assembly 1 onto a gantryinstallation worksite including through or via any train tunnel, traintrack or train station along the existing train route.

Optionally, a combined footprint of the post-installation conveyancesystem and gantry assembly supported thereon is accommodated by anexisting train route for bringing the gantry assembly off a gantryinstallation worksite and optionally onto a new gantry installationworksite including through or via any train tunnel, train track or trainstation along the existing train route.

Definitions

The phrase “horizontal alignment” means positioning on or with referenceto a horizontal surface or the x-y coordinates of a horizontal plane, asopposed to with reference to a vertical position, such that the gantryassembly, for example, is positioned correctly to align with positionson, along or adjacent to a path of travel, so that, for example, it isspaced correctly with respect to prepared support structures such as atie beam and/or the piers and/or is otherwise preferred e.g. for loadsupport e.g. placement at the point of greatest load tolerance e.g. thejuncture of two diagonally positioned struts or overlying an areaproximal to a vertical strut).

The term “horizontal” means “functionally horizontal” as appreciated bypersons skilled in the art having regard to any impact on stability withreference to context e.g. motion (transport plane) or stationary (e.g.support).

The term “end” as used herein, primarily to refer to the end of agantry, a track system or track or a bridge span. This term means an‘end portion’ of the structure in question, such that any supportprovided, leverage gained or strength feature etc. achieved at or fromthe end portion, yields a useful practical mechanical advantage,self-evident design choice or other intuitive benefit, for the purposesof the invention, as understood, in context, by persons skilled in therelevant arts. Hence, in practical contextual terms, “end” would not beunderstood to be limited to the geometric or linear end of the structureunless a person skilled in the art would consider implementation from ageometric end to be intended having regard to practical, predictabledesign considerations.

Similarly the term “proximal” means “functionally proximal” and ineffect connotes a distance or nearness aspect which for practicalpurposes is useful for realizing any purpose of the “proximity”(similarly understood, in context, from the standpoint of achieving anypractical mechanical advantage, design choice or other evidentorganizational benefit). For example, supporting a bridge span“proximal” to an end thereof would be understood to encompass apractical range of locations on the bridge span having regard to supportconsiderations as well as the consequent horizontal distance over whichthe bridge span would have to be transported to transfer the loadattributable to an end portion of the bridge span from the gantryconveyance system to the ground conveyance system. For example, thisdistance would be longer if the rigging suspending the bridge span wasattached to the bridge span closer to the end thereof. Similarly, thisdistance would be shorter if the very end of the bridge span was broughtto rest on a rail car of a ground conveyance system, as opposed to aportion more remote from the end.

The term “forward” when used to describe a rail car (first or secondground conveyance system) or a support member, suspension means orvehicle (gantry conveyance system) or an end of a gantry, gantryassembly, or bridge span, refers to that which is “leading” in theintended direction of transport. Similarly, the term “rear” or“rearward” refers to that which is “trailing”. It will be appreciatedthat the direction of transport, for convenience, may be the same forremoving an existing bridge span and bringing in a new or replacementbridge span from the opposite side of a bridge, however, as suggestedherein, in certain circumstances wherein the existing bridge span can beoff-loaded or removed from the railway relatively quickly, removal ofthe existing bridge span and installation of a replacement bridge spanmay be done from the same side of the bridge (i.e. the direction oftransport would be different).

The term “securely” used with reference to positioning of the groundengaging portions of the leg portions of the vertical support and liftsystem at the first ground locations, means that the ground engagingportions are at least operationally constrained from moving in ahorizontal plane so as to resist movement out of position and buckling.

The term “separately locatable” means that a component in question canbe separated, by a plurality of fixed distances or by a variable(continuous) distance from the remainder of a system or anothercomponent of the system such that it can, at least operatively, bepositioned independently. With respect to the gantry conveyance system,the phrase “separately locatable” implies that the vehicles can at leastbe separated to varying degrees but does not imply that they necessarilyhave independent methods of propulsion and that the vehicles have nocommon portions. Optionally, the component in question e.g. a vehicle,is unassociated i.e. completely independent e.g. of a second vehicle(“independently locatable”). By contrast, the term “independentlylocatable” further implies that the vehicles are fully independent in asense including being unlinked, independently controlled and driven byseparate propulsion sources (despite being functionally inter-dependent)for example, separate connection lines to a single or two hydraulicpower units

It will be appreciated that the strategy of having a pair ofhorizontally movable points of support e.g. suspension which areseparately or independently locatable” potentiates, at least in theory,“maximal” rearward movement of a forward point of support e.g.suspension (e.g. for conveying a new bridge span into position) and“maximal” forward movement of rearward point of support e.g. suspension(e.g. for removing an existing bridge span) enabling the bridge span tobe supported e.g. suspended proximal to its ends.

It will be appreciated that two separately locatable points ofsuspension may be conveyable, for example in a load-moving sense, intandem, for example by providing connection points at spaced positionsby which they become temporarily fixed to move together so that inprinciple only although both suspension means need to be conveyable atleast a passive sense if not actively (under some form of power) onlyone vehicle is needed for moving the load on the gantry conveyancesystem. Optionally both suspension means are conveyable under some formof power system, optionally both are sufficiently powered to move atleast half of a load corresponding to the weight of a bridge span.

The term “path” means any demarcated or non-demarcated area which is oris subject to being cleared to allow movement or transport.

The term “gantry conveyance system” is used to refer a conveyance systemsupported on the gantry.

The descriptors “first” and “second” as applied herein to groundconveyance systems used in conjunction with the gantry conveyancesystem, are used to refer to a system for removal of an existing bridgespan and a system for installation of a replacement bridge span,respectively. It will be appreciated that the at least one rail car usedas part of a ground conveyance system for removing an existing bridgespan may be reused on the same side of the gantry installation toinstall a replacement bridge span provided that the rail car(s) is/areable to be freed up for this purpose in a practical time frame.Irrespective of which rail cars are being used, the same side of gantrymay be used for both removal and installation of a bridge span providedthat the accommodating portion of track proximal to the pier in questioncan be accessed in a practical time frame for both activities. Subjectto the proviso that an existing bridge span is assumed to be availablefor installing a gantry assembly, the invention, is not limited to thecombined activities of removal and replacement of a bridge span and mayreside in either one of these activities independently as well as inpreliminary steps involved in installation of a gantry assembly foreither purpose. It will also be appreciated that the invention hereinhas application to installation of a gantry assembly for removal orinstallation of any type of bridge span.

The term “strap” means a length of material or connected materials ofsufficient length, strength, and rigidity or flexibility (from anengineering and safety standpoint) to serve the function of supportingsuch part of the weight of bridge span as is demanded by the context inwhich the strap is being used. The term strap includes, withoutlimitation, webbing and a cable. The webbing or cable optionally has aweight load limit of 50 tons. The term suspension means is used to referto a conveyable means for suspending the bridge span, a means whichserves a conveyance function and an attachment function. Optionally, theattachment function is accomplished by a length of material (e.g. astrap) of predetermined operational length i.e. in principle, the lengthis not varied in the course of operation to lower and raise the bridgespan in the fashion of a typical winch. In this connection, it isnoteworthy that the term “lift” as used in the context of a ‘verticalsupport and “lift” system’, connotes raising and lowering functionsdepending on the particular stage of the bridge span replacementprocess. Accordingly, the term “bridge span connection system” is usedto preferentially describe a length of material of predeterminedoperational length.

The term “sling” is used in broad functional terms to define parallelstraps or portions of a strap wherein the strap material is integrallylooped or connected to form a loop.

The term “rail car” includes any track engaging vehicle that is eitherpropelled (pushed or pulled) by another vehicle, such as a locomotive,or that is self-propelled, and preferably has a footprint adapted tonavigate through standard railway routes that lead to and from railwaybridges of the type that might require bridge span replacement forexample a lateral span of 5-14 feet, optionally 5 to 12 feet, forexample 6 to 10 feet.

In connection with a train car or rail car, the term “support platform”when used to describe a support portion of the car for a gantry organtry assembly is used to mean any type of load bearing surface used tosupport the weight of the gantry/gantry assembly. The term supportplatform is also used broadly to refer to a support bed constituted bycomplimentary surfaces of two cooperating rail cars.

The term “gantry” is a term of art and is broadly used herein to referto an elongate (optionally overhead) structure (generally understood toemploy conventional structural elements such as plates, struts, crossbars, beams etc. to garner strength while reducing the weight of thestructure) which includes or is operatively connected to anequipment-supporting sub-structure, for example, a sub-structure in theform of a platform or rails that support equipment, the equipmentaccording to the invention herein comprising at least one vehicle of agantry conveyance system, for example a vehicle propelled by an externalpower system or a self-propelled vehicle. In the context of a system orinstallation according to the invention as herein defined, the gantry isa horizontally positioned bridge span support structure that issupported by a support system e.g. vertically oriented legs that areoperatively associated with a lift system which vertical adjusts (i.e.raises and lowers) the height of the gantry so that the gantry togetherwith a bridge span suspended underneath it, can occupy a plurality ofvertical positions (e.g. height-adjusted substantially horizontalplanes) such that an existing bridge span can potentially be lifted offbridge-span support surfaces of two contiguous pier structures and a newbridge span lowered in its place.

The term “ground-support”, understood from the standpoint of providingload-bearing support for a gantry assembly, or a first or second groundconveyance system, is broadly understood to mean, in contradistinctionto support provided from the gantry, a load bearing ground-supportedsurface located at a height that is proximal to the height of the bridgespan support surfaces of the piers of a bridge (in need of spaninstallation or replacement), optionally in the case of a train-bridgeat or near track level. The invention contemplates that the groundsupport for the equipment required to replace a bridge span isessentially at “ground level” as defined herein i.e. roughly atbridge-height level. The invention contemplates that the ground supportis provided by the piers or from the surface of the ground leading to orfrom the bridge (approximately bridge height and not from the level atwhich the piers are supported). In principle, the direct support mayinclude any structure (apart from the gantry) directly or indirectlysupported on the ground area leading to or from the bridge at which atleast one bridge span is intended to be replaced or on a support surfacedirectly or indirectly supported on or constituted by the bridge pierslocated at the bridge in question. Indirect support may be provided byany load-bearing platform, pier, slab, beam or other support definingsurfaces (vehicular or stationary), which are in effect supported on theground, optionally at ground-level, optionally on ground material,optionally more proximal to the ground than the vertically elevatedhorizontal transport plane provided by the gantry conveyance system, forexample, support surfaces of a rail car or other vehicle of the typemore directly and proximally supported on the ground. Therefore, forexample, without limitation, particularly in the context of the phrase“first ground-support locations” which provide support for the gantryassembly leg portions, these locations may be a surface of a beam or aportion of a beam that laterally overhangs an adjacent bridge span, theadjacent bridge span providing ground support for the overhangingsupport portions of the support beam. Thus, the term “firstground-support locations” includes theoretical locations prepared forsupporting a gantry installation either in advance or as part theessential installation process. For example, the term “firstground-support locations”: encompasses terrestrial (directly orindirectly supported on the ground) or track-level aerial locations(e.g. overhang positions) in which primary or supplementaryground-associated support material remains to be physically installed,for example prior to and/or in the process of final positioning thegantry legs. As described below, first ground support locations areexemplified by portions 9A and 9C of a beam assembly that are optionallypre-fastened or temporarily fastened onto the ground engaging portionsof the gantry legs, as described below, and subsequently fastened ontoan earlier installed tie beam portion 9B which may positioned in placeof a standard railway tie prior to bringing a gantry assembly to thebridge span replacement site (alternatively called a “work site” or“installation site”).

In terms of “ground-support”, it will be appreciated that a support beddefined by support portions of a single or linked rail cars (notseparated in operation) of a first ground conveyance system may beconsidered to provide “ground support” for some form friction-reducedhorizontal conveyance of a bridge span to load a bridge span onto therail car, such as to obviate the need to employ a pair individuallylocatable rail cars. For example, the bridge span itself or a supportbed of the car may be outfitted with a form of slidable, rollable orotherwise friction-reduced means of facilitating horizontal travel sothat a single or linked rail cars (e.g. having a bridging platform) canreceive the bridge span incrementally. Similarly, the second groundconveyance system or a replacement bridge span may be outfitted with aform of slidable, rollable or otherwise friction-reduced means ofhorizontal movement such as to obviate the need to employ a pair ofindividually locatable rail cars to transfer load support from thesecond ground conveyance system to the gantry conveyance system.

The term “ground material” means any natural, man-made or partiallynatural and partially made material which constitutes the ground or partof the ground at first ground locations, second ground support locationsand/or third support ground location and may include coarse particulatematerial as well as material formed into platforms or structures of anytype so as to ultimately provide sufficient load support for rails,railway ties, rail cars etc. as well as an operational gantryinstallation. Typically ground material comprises a layer of coarseaggregate sitting on a layer(s) of substrate(s), however it will beappreciated that a wide variety of rails, railroad tie materials andstructures are known, and that rails be may supported on structures thatdo not employ railroad ties for support. Hence, the term ground materialencompasses a wide variety of materials. Ground material may support theends of unitary or multi-segment tie beam overhanging the sides on anadjacent bridge span.

The term “ground level” means a vertical position which approximatelycorresponds to a level at or above the height of a bridge pier or thesurface of a bridge span, optionally at a surface height of “groundmaterial” or the height of a support bed of a vehicle travelling on thebridge, optionally at a height approximating the height of vehiculartravel on the ground across the bridge.

The phrase “overhang ground-support system” means a system for providingground support from locations (e.g. aerial locations) adjacent to areasin which there is “actual” ground support material or a ground supportmeans, for example in load bearing ground-support structure that isspecially installed, for example abeam, optionally a tie beam.

The term “outrigger” is used to mean that the leg portion is distancedfrom the gantry. Hence, the “outrigger portion” of gantry connectionportion serves to distance the leg portion from the gantry.

The term “track level” means a vertical position approximatelycorresponding to the height of a train track, optionally a heightapproximately corresponding to a horizontal plane of travel on a trackrail or a height of a surface which supports a track rail.

The term “surface configuration”, used with reference describing thegantry assembly, means that the gantry assembly, optionally the gantryper se (which is optionally flat), has an exterior surface which issized and shaped to be supported, preferably in a horizontal position,by a shape-compatible support surface/means of a pre-installationconveyance system, compatibility in this respect being broadly definedsuch that any accessories or adjunct means of accomplishing the support(shims, wedges, rigging, adapter elements) whether commonly used orspecially designed, do not preclude compatibility. Support portions of apre-installation may be in the form of a bolster and may be of astationary, sliding or otherwise friction-reduced type to accommodate agantry of suitable length for replacement of the bridge span in question

The term “gantry assembly installation” as used herein, for example withreference to describing a bridge-span replacement installation, includesat least a horizontally oriented gantry 100 (see FIG. 1A) supportedproximal to each end thereof by a vertical support system adapted to beoperatively associated with a lift system including ground engagingload-bearing legs 20 which are positioned on the ground at load-bearingfirst ground-support locations located in the vicinity of the bridgespan support surfaces of two piers intended to be longitudinally spannedby the existing bridge span 6. Depending on the circumstances, theoptimal installation may dictate that the ground engaging portions ofthe leg portions 20 are secured to tie beams 9 positioned at the firstground-support locations.

The term “full gantry support” refers to a stage of removing an existingbridge span or installing a replacement bridge span in which the entireweight of the bridge span is borne by the gantry conveyance system.

The term “horizontal transport plane” refers to a vertically-elevated(relative to the support bed of a ground conveyance system) plane ofconveyance executed by the gantry conveyance system prior to partial orfull load transfer to the ground conveyance system and by both systemsin tandem. As far as the gantry conveyance system is concerned, thehorizontal limits of this plane of transport are absolutely defined (interms of theoretical maxima—in practice the vehicles may not be able toreach these theoretical maxima) by vehicle position limits imposed bythe track length of the gantry conveyance system 10. These limits areextendable by a ground conveyance system.

Small vertical adjustments in the horizontal transport plane may berequired for load transfer. In practice, though other forms of loadtransfer or vertical adjustment are possible (e.g. the height of thesupport bed of the ground conveyance system or partial release of thestraps may serve this purpose) using the lift system to slightly raiseor lower the bridge span within this principal transport plane may bethe easiest way to transfer part of the load to or from a groundengaging conveyance system.

The term “spreader structure” refers to an elongate load-bearing supportmember on the gantry conveyance system e.g. vehicle orientedtransversely with respect to the longitudinal axis of the gantry,optionally in the form of a steel beam that laterally distances pointsof attachment of a bridge span connection system from the centre ofgravity of the vehicle e.g. shackles supporting loops of strap-likematerial.

The term “track” or “track system” is used to describe any travel path(or system exploiting same) which potentially or actually interfaces orinteracts with a vehicle (as broadly defined), for example in the senseof defining a course (e.g. via a guard rail or guide member) which pathmay or not be an unchangeable path, and may or may not have a hold onthe vehicle. Preferably, the travel path imposes some restraint orcondition on the travel path (for example linearity) of a vehicle,serving, for example, as a stabilizing or security means, for examplevia any path defining means such an edge, rail, ridge, lip, rib,shoulder, channel etc. of any kind known to those skilled in the art.Such a path defining means may optionally fall into the category ofbeing principally male or female and may be both in some aspect and maybe also consist of or comprise spaced elements which are aligned in somefashion to collectively define or interact with mating or correspondingportions of a vehicle in a manner defining a travel path.

The term “vehicle” is used broadly to describe a movable load bearingconveyance device.

The term “vertical support and lift system” means a vertical supportsystem that is operatively associated with a lift system.

General System Design Parameters

A two sided gantry that provides a clearance way for members of asuspension system e.g. steel cables i.e. between the two sides of thegantry, can be adapted to accommodate railway clearances (10-13 feetwide) and adapted for using a gantry conveyance system consisting of onevehicle and a central single point type suspension system (e.g. aconveyable strand jack) or a two point suspension system (e.g. employingwinches). The gantry may be constructed with conventional structuralmembers including plate girders, box beams and trusses of suitable sizesand weight bearing capacities according to design parameters well knownto those skilled in the art.

A suspension system may employ well known underslung crane designsystems and related track system supported beneath the gantry of typeapplicable to heavy duty lift systems used in overhead horizontalconveyance systems, for example in which the trolley wheels ride on theflanges of a box beam or H beam type support structure.

With respect to parameters for designing a gantry assembly as describedin detail herein, it will be appreciated: the outrigger and leg portionsof the vertical support assemblies may be positioned at respectivehorizontal distances A and B from an end of the gantry; the positionsalong an existing bridge span to which the straps of the bridge spanconnection system are connected are located at horizontal distances Cand D from the end of the existing bridge span; the gantry conveyancesystem may comprise a track system and a forward vehicle and rearwardvehicle, and the ground conveyance system may comprise a forward railcar having a bridge span support surface and a rearward rail car havinga bridge span support surface; the forward vehicle rides and along thetrack system during conveyance of the bridge span in the horizontaltransport plane with a portion of the bridge span connection systemvertically suspended above the vertical height and within the lateralspan of the outrigger portion, the position of the outrigger portioninhibiting conveyance of the bridge span connection system past theposition of outrigger portion such that a longitudinal position of theoutrigger portion relative to an end of the gantry effectively defines aforward vehicle position limit; the length of gantry relative to lengthof the bridge span and the distances A, B, C and D accommodate alignmentof a forward end of the bridge span with second ground locationscorresponding to a support surface a forward rail car and alignment of arearward end of the bridge span with second ground locationscorresponding to a support surface of the rearward rail car.

In terms of replacing an existing bridge span, the outrigger and legportions of the vertical support assemblies are positioned at respectivehorizontal distances A and B from an end of the gantry; the positionsalong the bridge span to which straps of the bridge span connectionsystem are connected are located at horizontal distances C and D fromthe end of the bridge span; the gantry conveyance system comprises atrack system and a forward vehicle and rearward vehicle (capable ofmoving both forwardly and rearwardly); the second ground conveyancesystem comprises a forward rail car having a bridge span support surfaceand a rearward rail car having a bridge span support surface; the tracksystem defines a rearward vehicle position limit and the rearwardvehicle defines a forward vehicle position limit at a rearward end ofthe track system; the forward vehicle and rearward vehicle ride alongthe track system during conveyance of the bridge span in the horizontaltransport plane optionally with a portion of the bridge span connectionsystem vertically suspended above the vertical height of the outriggerportion and within the lateral span of the outrigger portion, theposition of the outrigger portion inhibiting positioning of the bridgespan connection system past the position of outrigger portion when thebridge span connection system is connected to the bridge span; thelength of gantry relative to length of the bridge span, the length ofthe forward vehicle, the length of the rearward vehicle, the length ofthe forward rail car, the length of rearward rail car, and the distancesA, B, C and D accommodate alignment of a forward end of the bridge spanwith a strap position limit of forward vehicle and alignment of arearward end of the bridge span with a strap position limit of therearward vehicle.

In terms of the pre-installation conveyance system, the support portionis a support platform having a platform footprint area including lateralperimeters; the gantry assembly defines a gantry assembly footprint areaincluding lateral perimeters; lateral clearance is affected by thecurvature of the train track; the track system is affixed on top thegantry; the height of gantry assembly on the pre-installation conveyancesystem and the lateral perimeters of platform footprint area and gantryassembly footprint area define a conveyance envelope that accommodatesexisting railway clearances for delivery of the gantry assembly to orfrom a site of removal and/or placement of a bridge span (e.g.approximately 18 feet); optionally the gantry has a substantially flatsurface configuration adapted to be supported on the support platformreducing the vertical size of the conveyance envelope, optionally the atleast one vehicle rides on top of the track system during deliveryand/or removal of the gantry assembly increasing the vertical size ofthe conveyance envelope.

In terms of the outrigger portion, the outrigger portion is preferablyconfigured to laterally distance the leg portions of the first verticalsupport assembly and the second vertical support assembly from lateralperimeters of the gantry, by a distance which accommodates passage of abridge span having up to a 13 foot wide footprint between the legportions of the first vertical support assembly and the second verticalsupport assembly.

EXAMPLE

A gantry may be approximately 150 feet in length). Railway clearancesdepending on the location may be approximately 14 feet wide and thelateral dimension of the gantry assembly with the outrigger portion andgantry legs positioned in a stowed position may be approximately 11-11.5feet and may be carried on a rail car having a conventional support deckof approximately 10 feet in width. A bridge span transported to a gantryassembly installation may have a lateral footprint which may beapproximately a foot shorter than the maximum lateral railway clearance.When the outrigger and leg portions of the vertical support assembliesare in an installation position they may provide a 9 inch plus clearanceon either side the bridge span, or a total clearance of approximately 14to 15 feet (e.g. 14.5 feet), the centers of gantry legs laterallyspanning approximately 15 to 16 feet (e.g. 15.5 feet) and supported onsupport beams (alternatively termed tie beams) of approximately 16 feetin length. The gantry may have a narrower footprint than thepre-installation conveyance system (and the spreader beam on top ofvehicles of the gantry conveyance system may be a lateral lengthsufficient to allow the straps to hang vertically and freely about thegantry when connected to the bridge span (e.g. approximately 7 feet).

Strictly by way of example, a bridge span of approximately 125-150 tonsand 90-110 feet in length may be supported by a gantry of 140-160 feetin length supported by four hydraulically powered leg portions operatingto lift a combined weight lift of approximately 300 tons (combinedweight of bridge span, gantry and gantry conveyance system).

According to one aspect the invention is directed to use of a gantryinstallation in which the bridge span is suspended in the horizontaltransport plane under safe wind conditions e.g. in which the wind speedis preferably less than 30 km/hour.

It will be appreciated that each embodiment of the invention(s)described herein has application to the various aspects of the inventionincluding method, system, gantry assembly installation and gantryassembly. Therefore, save for method steps involving a particularaction, each embodiment shall be considered to have general applicationto each aspect of the invention and each other embodiment. Method stepsshall have application to the use of a gantry assembly installation,gantry assembly and system as variously defined herein for removing anexisting bridge span or installing a replacement bridge span in itsplace, or both e.g. to a use in accordance with any embodiment of themethod.

While the above description constitutes a plurality of embodiments ofthe present invention, it will be appreciated that the present inventionis susceptible to further modification and change without departing fromthe fair meaning of the accompanying claims.

We claim:
 1. A method of removing an existing train bridge span, of thetype supported on two piers of a train bridge, when installing areplacement train bridge span, the existing train bridge span supportinga length of track overlying the existing bridge span that is in linewith a railroad track extending between railroad service areas on eitherside of the bridge, the method comprising: (a) using the railroad trackto bring a gantry assembly including a gantry, on a rail vehicle, fromone side of the train bridge into horizontal alignment withground-support locations such that the gantry assembly is positionedover the existing bridge span, the ground support locations supporting avertical load predetermined to accommodate lifting the existing bridgespan with the gantry assembly and located to provide support atpositions on both sides of the bridge and on both sides of the railroadtrack, the positions predetermined to accommodate lifting the existingtrain bridge span from beneath the gantry assembly and conveying theexisting train bridge span away from beneath the gantry assembly; (b)causing the gantry assembly to self-lift off the rail vehicle onto theground support locations; (c) lifting the existing train bridge span offthe two piers of the train bridge; (d) conveying the existing trainbridge span underneath the gantry; (e) lowering the existing trainbridge span onto a rail conveyance system positioned beneath the gantryassembly; and (f) removing the existing train bridge span from beneaththe gantry assembly on the rail conveyance system.
 2. A method accordingto claim 1, wherein the ground support locations on opposite sides ofthe bridge are positioned at a distance from one another which spans asection of the railroad track that is greater than the length of trackoverlying the existing train bridge span.
 3. A method according to claim1, wherein the ground support locations, on immediately opposite sidesof the railroad track, are positioned at a distance from one anotherwhich allows a rail conveyance system carrying a bridge span with afootprint wider than the gantry to pass in and out from beneath thegantry assembly.
 4. A method according to claim 2, wherein the groundsupport locations, on immediately opposite sides of the railroad track,are positioned at a distance from each other which allows a railconveyance system carrying a bridge span with a footprint wider than thegantry to pass in and out from beneath the gantry assembly.
 5. A methodaccording to claim 2, further comprising the step of installing supportbeams under the track at both ends of the predetermined section of therailroad track.
 6. A method according to claim 5, further comprising thestep of securing ground engaging portions of the gantry assembly to thesupport beams.
 7. A method according to claim 1, further comprising thesteps of conveying the replacement train bridge span underneath thegantry assembly on a rail conveyance system; lifting the replacementbridge span; conveying the replacement train span underneath the gantryinto a position overlying bridge span support surfaces of the piers; andlowering the replacement train bridge span onto the bridge span supportsurfaces.
 8. A method according to claim 4, wherein the gantry assemblyincludes a vertical support and lift system including outrigger portionsand leg portions extending vertically from the outrigger portions,wherein the leg portions are in a retracted position above the railroadtrack when the gantry assembly is first brought in on the rail vehiclefrom one side of the train bridge, and wherein the vertical support andlift system is operable to extend the leg portions from the retractedposition to cause the gantry assembly to self-lift onto theground-support locations.
 9. A method according to claim 8, whereinoutrigger portions are movable between a stowed position in which theoutrigger portions are rotated towards the gantry and a laterallyextended position, and wherein the outrigger portions are in a stowedposition when the gantry assembly is first brought in on the railvehicle from one side of the train bridge, and wherein the outriggerportions are moved into and secured in laterally extended positionsbefore the vertical support and lift system causes the gantry assemblyto self-lift onto the ground-support locations.
 10. A gantry assemblyinstallation adapted for removing an existing train bridge span, of thetype supported on two piers of a train bridge, and installing areplacement train bridge span, the existing train bridge span supportinga length of track overlying the existing bridge span that is in linewith a railroad track extending between railroad service areas on eitherside of the bridge, the gantry assembly installation comprising: agantry assembly including a gantry and vertical support and lift system,the gantry assembly including leg portions, the leg portions includingground engaging portions secured to ground-support locations, the groundengaging portions positioned to provide vertical support for the gantryassembly at positions on both sides of the bridge and on both sides ofthe railroad track such that the existing train bridge span can belifted from beneath the gantry assembly and conveyed away from thebridge from beneath the gantry assembly; the ground support locationssupporting a vertical load predetermined to accommodate lifting theexisting bridge span with the gantry assembly and predetermined to alignwith ground engaging portions of the leg portions.
 11. A gantry assemblyinstallation according to claim 10, wherein the ground engagingportions, on the same side of the railroad track, are positioned at adistance from one another across the bridge which spans a section of therailroad track that is greater than the length of track overlying theexisting train bridge span.
 12. A gantry assembly installation accordingto claim 10, wherein the ground engaging portions, on immediatelyopposite sides of the railroad track, are positioned at a distance fromone another which allows a rail conveyance system carrying a trainbridge span with a footprint wider than the gantry to pass in and outfrom beneath the gantry assembly.
 13. A gantry assembly installationaccording to claim 11, wherein the ground engaging portions, onimmediately opposite sides of the railroad track, are positioned at adistance from each other which allows a rail conveyance system carryinga train bridge span with a footprint wider than the gantry to pass inand out from beneath the gantry assembly.
 14. A gantry assemblyinstallation according to claim 11, wherein the ground engaging portionsare secured to support beams under the track located at both ends of thesection of the railroad track.
 15. A gantry assembly installationaccording to claim 13, wherein the vertical support and lift systemincludes outrigger portions, the leg portions extending vertically fromthe outrigger portions.
 16. A gantry assembly installation according toclaim 15, wherein the outrigger portions are configured to be movablebetween a stowed position in which the outrigger portions are rotatedtowards the gantry and a laterally extended position, and wherein theoutrigger portions are secured in laterally extended positions when thegantry assembly is installed at the ground support locations.
 17. Agantry assembly installation according to claim 15, wherein the verticalsupport and lift system is operatively connected to a power system and acontrol system, the power system and control system operable to vary thelinear vertical distance between the ground engaging portions of the legportions and the gantry, and to control the vertical height of thegantry when the existing train bridge span or the replacement trainbridge span is suspended from the gantry.
 18. A gantry assemblyinstallation according to claim 10, further comprising a gantryconveyance system, the gantry conveyance system including a track and atleast one vehicle configured to ride along the track.
 19. A gantryassembly installation according to claim 18, wherein the gantryconveyance system is operatively associated with a bridge spanconnection system for suspending the bridge span from the gantryconveyance system, the gantry conveyance system and bridge spanconnection system configured to provide at least two conveyable,separately locatable, suspension means for suspending the bridge spanbeneath the gantry.
 20. A gantry assembly installation according toclaim 18, wherein the gantry conveyance system includes twoindependently locatable vehicles.
 21. A gantry assembly installationaccording to claim 15, further comprising a rail conveyance systemoperable to convey an existing bridge span away the train bridge frombeneath the gantry assembly.
 22. A gantry assembly installationaccording to claim 21, wherein the rail conveyance system includes tworail cars, the two rail cars having a combined length which allows bothrail cars to be positioned underneath the gantry assembly, on one sideof the train bridge, between the positions of the ground engagingportions and the length of track overlying the existing train bridgespan.
 23. A gantry assembly installation according to claim 15, furthercomprising a rail conveyance system operable to convey the replacementtrain bridge span towards the train bridge under the gantry assembly.24. A gantry assembly installation according to claim 23, wherein therail conveyance system includes two rail cars, the two rail cars havinga combined length which allows both rail cars to be positionedunderneath the gantry assembly, on one side of the train bridge, betweenthe positions of the ground engaging portions of the leg portions andthe length of track overlying the existing train bridge span.